Teenagers | 2008

In every motorized country, teenage drivers represent a major hazard. In the United States, teenagers drive less than all but the oldest people, but their numbers of crashes and crash deaths are disproportionately high. Insurance Institute for Highway Safety. 2008. [Unpublished analysis of data from the US Department of Transportation's National Household Travel Survey, General Estimates System, and Fatality Analysis Reporting System]. Arlington, VA. In the United States, the crash rate per mile driven for 16-19 year-olds is 4 times the risk for older drivers. Risk is highest at age 16. In fact, the crash rate per mile driven is twice as high for 16 year-olds as it is for 18-19 year-olds.

Until the mid 1990s, most U.S. states allowed teens to get full-privilege licenses at an earlier age than in most other countries, and little driving experience typically was required prior to licensure. The result was greatly elevated crash risk among young drivers. As more and more states have adopted graduated licensing systems, which phase in full driving privileges, the crash rates in these states have declined about 10-30 percent. Ulmer, R.G.; Preusser, D.F.; Williams, A.F.; Ferguson, S.A.; and Farmer, C.M. 2000. Effect of Florida's graduated licensing program on the crash rate of teenage drivers. Accident Analysis and Prevention 32:527-32. Shope, J.T. and Molnar, L.J. 2004. Michigan's graduated driver licensing program: evaluation of the first four years. Journal of Safety and Research 35:337-44. Foss, R.D.; Feaganes, J.R.; and Rodgman, E.A. 2001. Initial effects of graduated driver licensing on 16-year-old driver crashes in North Carolina. Journal of the American Medical Association 286:1588-92. Governor's Highway Safety Office. 2001. Review of Ohio's graduated driver license program. Columbus, OH: Ohio Department of Public Safety. Mayhew, D.R.; Simpson, H.M.; Des Groseilliers, M.; and Williams, A.F. 2001. Impact of the graduated driver licensing program in Nova Scotia. Journal of Crash Prevention and Injury Control 2:179-92. Zhu, M.; Chu, H.; and Li, G. 2009. Effects of graduated driver licensing on licensure and traffic injury rates in upstate New York. Accident Analysis and Prevention 41:531-35. Hallmark, S.L.; Veneziano, D.A.; Falb, S.; Pawlovich, M.; and Witt, D. 2008. Evaluation of Iowa's graduated driver's licensing program. Accident Analysis and Prevention 40:1401-05. A national study of graduated licensing laws found that laws the Institute rated good were associated with substantially lower fatal crash rates among teen drivers, and substantially lower insurance claim rates, than laws rated poor. Strong restrictions on nighttime and teen passengers, as well as delayed licensing age, also reduced rates of fatal crashes and insurance collision claims. McCartt, A.T.; Toeh, E.R.; Fields, M.; Braitman, K.A.; and Hellinga, L.A. 2009. Graduated licensing laws and fatal crashes of teenage drivers: a national study. Arlington, VA: Insurance Institute for Highway Safety. Trempel, R.E. 2009. Graduated driver licensing laws and insurance collision claim frequencies of teenage drivers. Arlington, VA: Highway Loss Data Institute. Crash rates for young drivers are high largely because of their immaturity combined with driving inexperience. The immaturity is apparent in young drivers' risky driving practices such as speeding and tailgating. At the same time, teenagers' lack of experience behind the wheel makes it difficult for them to recognize and respond to hazards. Fatal crashes involving young drivers typically are single-vehicle crashes and often involve driver error and/or speeding. They often occur when other young people are in the vehicle with the young driver, so teenagers are disproportionately involved in crashes as passengers as well as drivers. Chen, L-H.; Baker, S.P.; Braver, E.R.; and Li, G. 2000. Carrying passengers as a risk factor for crashes fatal to 16- and 17-year-old drivers. Journal of the American Medical Association 283:1578-82.

The following facts are based on analysis of data from the U.S. Department of Transportation's Fatality Analysis Reporting System (FARS).

Trends

A total of 4,054 teenagers ages 13-19 died in motor vehicle crashes in 2008. This is 54 percent fewer than in 1975 and 19 percent fewer than in 2007. About 2 out of every 3 teenagers killed in motor vehicle crashes in 2008 were males. Since 1975 teenage motor vehicle crash deaths have decreased more among males (59 percent) than among females (38 percent).

Teenage motor vehicle deaths by gender, 1975-2008

Motor vehicle crash deaths among 13-19 year-olds by gender, 1975-2008
YearMaleFemaleTotal*
Num%Num%Num
19756,532752,215258,748
19766,826732,530279,356
19776,983722,650289,633
19787,295732,645279,940
19797,280732,639279,920
19806,932732,591279,524
19816,014722,301288,315
19825,354731,969277,323
19834,850711,955296,805
19844,947712,005296,952
19854,715702,022306,737
19865,280712,182297,466
19875,107702,186307,293
19885,036702,204307,242
19894,528682,158326,688
19904,420691,944316,364
19913,891681,867325,760
19923,495671,713335,215
19933,678681,742325,421
19943,770671,859335,632
19953,702651,970355,675
19963,855661,963345,819
19973,715652,014355,730
19983,649651,960355,610
19993,745652,007355,752
20003,759661,925345,685
20013,735671,859335,594
20023,939662,015345,954
20033,772661,946345,718
20043,696651,948355,645
20053,496661,803345,300
20063,415661,744345,159
20073,280661,701344,981
20082,681661,370344,054
*Total includes other and/or unknowns

Teenagers accounted for 10 percent of the US population in 2008 and 11 percent of motor vehicle crash deaths. They comprised 13 percent of passenger vehicle (cars, pickups, SUVs, and vans) occupant deaths among all ages, 7 percent of pedestrian deaths, 4 percent of motorcyclist deaths, 11 percent of bicyclist deaths, and 22 percent of all-terrain vehicle rider deaths.

US teenage and total population, 2008
Teen populationTotal population% Teens of total population
29,710,307304,059,72410
Teenage motor vehicle crash deaths as percent of all motor vehicle crash deaths, 2008
Death typeTeen motor
vehicle deaths
Motor vehicle deaths
for all ages
% teen deaths
of all motor vehicle deaths
Passenger vehicle occupant3,26925,42813
Pedestrian3184,3787
Motorcyclist2255,0914
Bicyclist7871411
All-terrain vehicle riders8337522
Other811,2756
Total*4,05437,26163
*Total includes other and/or unknowns

Eighty-one percent of teenage motor vehicle crash deaths in 2008 were passenger vehicle occupants. The others were pedestrians (8 percent), motorcyclists (6 percent), bicyclists (2 percent), riders of all-terrain vehicles (2 percent), and people in other kinds of vehicles (2 percent).

Teenage motor vehicle crash deaths by type and age, 2008
AgePassenger vehicle occupantsMotorcyclistsPedestriansBicyclistsAll-terrain
vehicle riders
OtherTotal motor vehicle deaths*
Num%Num%Num%Num%Num%Num%Num
135955222422878776108
1412062953015158105105194
151966972461614514593286
164608317339761193143555
1764585324476101101111755
189288563662617291811,087
1986181959707811312221,069
Total3,26981225631887828328124,054
*Total includes other and/or unknowns

In 2006, the latest year for which data are available, motor vehicle crashes were the leading cause of death among 13-19 year-old males and females in the United States. Thirty-three percent of deaths among 13-19 year-olds occurred in motor vehicle crashes, 39 percent among females and 31 percent among males.

Leading causes of death among teenagers by gender, 2006
Cause of deathMaleFemaleTotal
Motor vehicles3,4151,7445,159
Homicide2,1063372,443
Suicide1,3703481,718
Malignant neoplasms515345860
Motor vehicle crash deaths as a percent of deaths from all causes by gender and age, 2006
AgeMaleFemaleTotal*
MV deathsAll deaths%MV deathsAll deaths%MV deathsAll deaths%
< 529418,521228514,637257933,1582
5-92921,551192271,184195192,73519
10-1217196918161695233321,66420
13-154532,044222941,120267473,16424
16-171,0903,405326851,471471,7754,87636
18-191,8725,574347651,875412,6377,44935
20-244,57716,152281,3804,996285,95721,14828
25-293,11815,181219245,716164,04220,89719
30-5913,180263,70255,000159,480318,182423,1824
60-692,097186,33511,096133,89613,194320,2311
≥ 702,627688,508< 12,007899,252< 14,6361,587,760< 1
*Total includes other and/or unknowns
NOTE: Data on motor vehicle crashes come from FARS.
Data on other causes of death come from U.S. Centers for Disease Control and Prevention(CDC)

Drivers and passengers in passenger vehicles

In 2008, 60 percent of deaths among passenger vehicle occupants ages 16-19 were drivers.

Passenger vehicle teenage occupant deaths by age and seating position, 2008
AgeDriverPassengerTotal*
Num%Num%Num
1335569559
1410811092120
15341716283196
162305022950460
173475429446645
185906433236928
195776728133861
Total1,791551,464453,269
*Total includes other and/or unknowns

Sixty-three percent of teenage passenger deaths in 2008 occurred in vehicles driven by another teenager. Among deaths of passengers of all ages, 19 percent occurred when a teenager was driving.

Passenger vehicle passenger deaths by passenger age and driver age, 2008
Passenger ageDriver ageAll ages*
13-1920-2425-2930-5960-69≥ 70
Num%Num%Num%Num%Num%Num%Num
< 1355810115153223565119391696
13-199216325517725191131414< 11,464
20-24183175194917917164155< 13< 11,066
25-29568172262163220531413< 1666
30-59102519710232121,2046212065431,931
60-6910312311315039147385314386
≥ 70111162111270291341449553941
All ages*1,339191,27618877122,54836445662397,174
*Total includes other and/or unknowns

In 2008, belt use among fatally injured drivers ages 16-19 (41 percent) was higher than among fatally injured drivers ages 20-29 (34 percent) but lower than among drivers 30 and older combined (46 percent). Among fatally injured 16-19 year-old occupants, belt use among passengers (32 percent) was considerably lower than among drivers (41 percent). Note that belt use among those fatally injured is not always accurately recorded, but it gives an indication of relative belt use rates in serious crashes by age group.

Seat belt use among fatally injured passenger vehicle occupants by age and seating position, 2008
AgePassengersDrivers
Belt usedUnbeltedUnknownBelt usedUnbeltedUnknown
Num%Num%Num%Num%Num%Num%
13213834611200310000
14322965591312110880110
1534211126916101647175013
167432135592091104810747136
1710536165562481544417651175
1894282036135112434130552427
1986311635832112103631855498
20-242992867663919936361,480562168
25-291832743766467626321,179601488
30-59689361,1035713973,099404,122535267
60-69232601393615486753653401026
≥ 7067672224244141,49361766311817
Total*2,884403,7295253177,757439,143501,3017
*Total includes other and/or unknowns

Among passenger vehicle drivers ages 16-19 involved in fatal crashes in 2008, 49 percent were involved in single-vehicle crashes. This was the same for drivers ages 20-24 (49 percent) but higher than for drivers ages 25 and older (38 percent).

Passenger vehicle drivers in fatal crashes by age and crash type, 2008
 Single vehicleMultiple vehicleAll crashes *
Num%Num%Num
16-191,955492,070514,028
20-242,788492,950515,743
25-292,027452,447554,479
30-596,9423910,9986117,948
60-691,143362,068643,216
≥ 701,097302,617703,716
*Total includes other and/or unknowns

Population and mileage rates

From 1975 to 2008, the rate of deaths per 100,000 people declined by 54 percent for teenagers (from 29.4 to 13.6 per 100,000). In contrast, the death rate declined by 75 percent for people 12 and younger (from 7.9 to 2.0 per 100,000), 36 percent for people ages 20-69 (from 22.4 to 14.3 per 100,000), and 40 percent for people 70 and older (from 25.9 to 15.5 per 100,000).

Motor vehicle crash deaths per 100,000 people by age group, 1975-2008
 < 1313-1920-69≥ 70
PopulationNumratePopulationNumratePopulationNumratePopulationNumrate
197545,851,3043,6437.929,795,0238,74829.4125,762,92728,15422.414,563,9453,77525.9
197645,000,7043,4247.629,909,4149,35631.3128,164,92628,65422.414,960,1203,89626.0
197744,337,3323,3477.529,800,3139,63332.3130,700,53130,74723.515,401,2493,85925.1
197843,907,4673,3677.729,543,2529,94033.6133,257,28532,90624.715,876,5413,82424.1
197943,778,9593,1717.229,077,6079,92034.1135,810,30433,90725.016,388,6173,77223.0
198043,914,3423,0486.928,486,4879,52433.4137,925,91334,32924.916,897,9773,86122.8
198144,049,9402,7336.227,743,9478,31530.0140,349,00733,83724.117,322,7143,87122.3
198244,131,5962,5735.827,160,5867,32327.0142,588,42630,15021.117,783,8883,65520.6
198344,119,2972,5185.726,737,4976,80525.5144,701,35829,34120.318,233,7513,73420.5
198443,978,0442,4225.526,435,8856,95226.3146,747,91630,58520.818,662,9384,05221.7
198544,260,1362,4695.626,001,2476,73725.9148,589,56430,15720.319,072,7854,20622.1
198644,755,4542,5375.725,592,4817,46629.2150,321,42631,39520.919,463,4804,44522.8
198745,348,2472,6545.925,209,6157,29328.9151,840,34431,75020.919,890,8174,55522.9
198845,942,9662,7015.925,004,4457,24229.0153,249,14532,07120.920,302,2804,92524.3
198946,690,6042,6585.724,664,3006,68827.1154,744,81831,16320.120,719,3974,94323.9
199047,472,5272,3324.924,404,7956,36426.1156,422,79130,93419.821,164,2834,84422.9
199148,240,7472,2574.724,066,5875,76023.9158,093,86128,53618.121,751,8974,84322.3
199248,903,6682,1654.424,163,1755,21521.6159,641,63926,85916.822,321,2174,90122.0
199349,335,8642,1644.424,664,0915,42122.0160,981,98027,20416.922,800,6735,22122.9
199449,692,4622,3014.625,219,8385,63222.3162,170,87627,27116.823,243,8455,42523.3
199549,920,4842,2014.425,764,3005,67522.0163,424,73528,34817.323,693,7575,50923.3
199650,085,1882,1864.426,357,1985,81922.1164,729,86328,36517.224,056,3235,57823.2
199750,364,9832,1084.226,730,8125,73021.4166,278,99528,19417.024,408,8175,87224.1
199850,527,4762,0324.027,174,7285,61020.6167,752,24827,97016.724,793,5515,79823.4
199950,667,1391,9973.927,518,1565,75220.9169,412,71328,22416.725,092,8055,65722.5
200052,219,4231,8883.628,326,4125,68520.1176,086,44828,87416.425,559,8795,37921.0
200152,341,3951,7513.328,437,7115,59419.7178,525,50229,30916.425,797,4675,42521.0
200252,332,3061,6173.128,644,3135,95420.8180,959,27529,98316.626,005,3265,33220.5
200352,187,6021,6433.129,028,5005,71819.7183,371,92830,07016.426,200,9465,36320.5
200452,151,4061,6453.229,400,3925,64519.2185,766,08830,32716.326,337,5185,10619.4
200552,149,3951,5292.929,589,8545,30017.9188,012,48631,51416.826,658,6695,04718.9
200652,306,9081,4302.729,772,1985,15917.3190,434,58031,37516.526,884,7984,63617.2
200752,585,8091,2692.429,775,9434,98116.7192,123,88830,25615.727,135,5174,63117.1
200852,929,7791,0452.029,710,3074,05413.6193,898,60427,81514.327,521,0344,26815.5

The rate of deaths per 100,000 people in 2008 peaked at age 19 for male drivers (18.7 per 100,000) and at age 18 for male passengers (8.6 per 100,000). Death rates peaked at age 18 for both female drivers (8.7 per 100,000) and female passengers (6.3 per 100,000).

Deaths in passenger vehicles per 100,000 people by seating position, age, and gender, 2008

Deaths in passenger vehicles per 100,000 people by seating position, age, and gender, 2008
AgeMaleFemaleTotal
PopulationDriver deathsPassenger deathsPopulationDriver deathsPassenger deathsPopulationDriver deaths *Passenger deaths *
NumRateNumRateNumRateNumRateNumRateNumRate
< 1327,071,74200.03831.425,858,03710.03131.252,929,77910.06961.3
132,090,42810.0361.71,990,28420.1201.04,080,71230.1561.4
142,107,27140.2612.92,007,96660.3492.44,115,237100.21102.7
152,152,832241.1743.42,047,109100.5884.34,199,941340.81623.9
162,186,0951496.81386.32,086,274813.9914.44,272,3692305.42295.4
172,225,1492209.91707.62,118,6611276.01245.94,343,8103478.02946.8
182,270,76840317.71968.62,155,0421878.71366.34,425,81059013.33327.5
192,192,42041018.71737.92,080,0081668.01085.24,272,42857613.52816.6
20-2410,845,4281,99818.47256.710,213,5536346.23413.321,058,9812,63212.51,0665.1
25-2910,940,9561,50113.74354.010,392,7874524.32312.221,333,7431,9539.26663.1
30-5962,140,7885,5078.91,0191.662,913,6742,2403.69121.4125,054,4627,7476.21,9311.5
60-6912,542,1411,1088.81501.213,909,2775133.72361.726,451,4181,6216.13861.5
≥ 7011,158,5861,63314.62982.716,362,4488064.96433.927,521,0342,4398.99413.4
*Total includes other and/or unknowns

The rate of fatal passenger vehicle crash involvements per 100 million miles traveled in 2001-02 was highest at ages 16-17 for male drivers and at age 16 for female drivers. Insurance Institute for Highway Safety. 2008. [Unpublished analysis of data from the US Department of Transportation's National Household Travel Survey, General Estimates System, and Fatality Analysis Reporting System]. Arlington, VA.

Fatal passenger vehicle crash involvements per 100 million miles traveled by driver age and gender, April 2001-March 2002
AgeMalesFemalesTotal*
Crash involvementsMilesRateCrash involvementsMilesRateCrash involvementsMilesRate
166455,813,200,81211.13765,178,574,3037.31,02110,991,775,1169.3
179818,852,565,18811.14298,154,664,7685.31,41017,007,229,9578.3
181,28216,804,407,9407.650810,771,468,1744.71,79027,575,876,1146.5
191,34714,957,220,0709.053811,159,768,8594.81,88526,116,988,9287.2
20-245,36594,285,456,4435.71,81972,854,283,3382.57,184167,139,739,7804.3
25-293,528131,714,125,4172.71,34483,429,400,6171.64,873215,143,526,0352.3
30-5914,904845,507,965,6891.86,927551,350,306,4301.321,83113968582721191.6
60-692,088128,814,817,8451.61,00664,778,212,7901.63,094193,593,030,6351.6
≥ 703,14576,991,652,5604.11,57139,093,332,0094.04,716116,084,984,5694.1
*Total includes other and/or unknowns

The rate of nighttime fatal passenger vehicle crash involvements per 100 million miles traveled in 2001-02 was almost 6 times higher for male drivers ages 16-19 than for male drivers ages 30-59. The corresponding comparison for females yields 3 times the rate. Insurance Institute for Highway Safety. 2008. [Unpublished analysis of data from the US Department of Transportation's National Household Travel Survey, General Estimates System, and Fatality Analysis Reporting System]. Arlington, VA.

Nighttime (9pm-6am) fatal passenger vehicle crash involvements
per 100 million miles traveled by driver age and gender, April 2001-March 2002
AgeMalesFemales
Crash involvementsMilesRateCrash involvementsMilesRate
16-191,7536,868,242,23025.55585,288,492,85810.6
20-294,38734,863,762,48612.61,02116,250,031,8666.3
30-594,659100,198,843,5834.61,49942,841,189,8213.5
60-693348,575,497,3493.9973,894,479,5172.5
≥ 702433,451,274,2997.0731,370,058,2965.3

When teenagers died

In 2008, August had the highest number of teenage crash deaths of any month.

Teenage motor vehicle crash deaths by month, 2008
MonthDeaths%
January3017
February2767
March3148
April3258
May3529
June3328
July3759
August39410
September3138
October3489
November3709
December3549
Total4,054100

Fifty-five percent of motor vehicle crash deaths among teenagers in 2008 occurred on Friday, Saturday, or Sunday.

Teenage motor vehicle crash deaths by day of week, 2008
Day of weekDeaths%
Sunday76119
Monday46512
Tuesday44011
Wednesday43611
Thursday47412
Friday68117
Saturday79720
Total*4,054100
*Total includes other and/or unknowns

Twenty percent of teenage motor vehicle crash deaths in 2008 occurred between 9 pm and midnight.

Teenage motor vehicle crash deaths by time of day, 2008
Time of dayDeaths%
Midnight-3am59915
3am-6am39010
6am-9am3368
9am-noon2606
Noon-3pm41510
3pm-6pm59715
6pm-9pm62015
9pm-midnight80020
Total*4,054100
*Total includes other and/or unknowns

Alcohol involvement

Young drivers are less likely than adults to drive after drinking alcohol, but their crash risk is substantially higher when they do. This is especially true at low and moderate blood alcohol concentrations (BACs). Peck, R.C; Gebers, M.A.; Voas, R.B.; and Romano, E. 2008. The relationship between blood alcohol concentration (BAC), age, and crash rise. Journal of Safety Research 39:311-19. The estimated percentage of fatally injured passenger vehicle drivers ages 16-17 who had BACs at or above 0.08 percent in 2008 was 16 percent, down 60 percent since 1982. Most of this decline took place in the 1980s. This age group experienced the greatest decline in alcohol involvement, compared with a 45 percent decline for drivers ages 18-20, a 15 percent decline for drivers ages 21-30, and a 32 percent decline for drivers older than 30.

Percent of fatally injured passenger vehicle drivers with BACs ≥ 0.08 percent by age, 1982-2008

Estimated percent and number of fatally injured passenger vehicle drivers with BACs ≥ 0.08 percent by age group, 1982-2008
YearAges 16-17Ages 18-20Ages 21-30Ages > 30
Drivers killedEstimated drivers killed with BAC ≥ 0.08Drivers killedEstimated drivers killed with BAC ≥ 0.08Drivers killedEstimated drivers killed with BAC ≥ 0.08Drivers killedEstimated drivers killed with BAC ≥ 0.08
NumNum%NumNum%NumNum%NumNum%
1982895368412,5611,458576,2443,948639,8614,20843
1983899345382,4271,336556,0533,859649,8453,94340
1984969321332,4721,274526,4123,8856110,3373,86037
1985935250272,2921,009446,2623,6595810,4413,71336
19861,172336292,4641,158476,6953,9745911,0423,88735
19871,192311262,4381,004416,8023,9755811,5794,01635
19881,177302262,6111,056406,8193,9915912,1454,20335
19891,060234222,476991406,4753,6755712,4014,27234
1990999224222,398974416,1523,5105712,2744,23835
1991902193212,119852405,6233,1835711,8013,99334
1992900165181,797664375,1222,7595411,6393,82333
1993935152161,870643345,0652,6585212,0383,85132
19941,006167171,984632324,9752,4845012,5253,77130
19951,015150151,968575295,0812,5855113,2464,15531
19961,106186171,920583304,9892,4755013,4784,07030
19971,090180171,946594314,7752,2754813,7774,00429
19981,059161152,035607304,5772,2224913,8393,93028
19991,092172162,169677314,6532,2604913,8703,86628
2000999158162,251686304,7062,2684813,7433,99729
2001993132132,254691314,7352,3585013,7904,00529
20021,126155142,326718314,9382,4625014,0064,02029
2003994159162,266699314,8522,3084813,9573,93028
2004969149152,206665304,9702,3724813,6893,74327
2005879132152,106603295,0672,4924913,8093,85228
2006859151182,161680315,1592,5354913,3213,77928
2007775133171,953633325,0282,5925212,6973,67529
200857794161,712535314,3712,3455411,4783,33629

Fatally injured female teenage drivers were less likely than male teenage drivers in 2008 to have high BACs. Among fatally injured passenger vehicle drivers ages 16-17, 20 percent of males and 10 percent of females in 2008 had BACs at or above 0.08 percent. Among fatally injured drivers ages 18-19, 34 percent of males and 17 percent of females had BACs at or above 0.08 percent.

Estimated percent and number of fatally injured passenger vehicle drivers with BACs≥0.08 percent by gender and age, 2008
AgeMaleFemaleTotal*
Drivers killedEstimated drivers killed with BAC ≥ 0.08Drivers killedEstimated drivers killed with BAC ≥ 0.08Drivers killedEstimated drivers killed with BAC ≥ 0.08
NumNum%NumNum%NumNum%
16-17369742020820105779416
18-198132793435359171,16733829
2040616541139322354519736
21-303,3411,987591,030358354,3712,34554
31-605,3932,423452,227577267,6203,00139
61-701,081180174892141,57120213
> 701,52611377602132,2871346
All ages*12,9695,240405,2261,0912118,2016,33235
*Total includes other and/or unknowns

References