Figure 8.4 is a stacked bar graph showing past year illicit drug or alcohol dependence or abuse by age group and substance in 2002. For youths aged 12 to 17, rates of substance dependence or abuse were 3.0 percent for alcohol only, 3.4 percent for illicit drugs only, and 2.5 percent for both alcohol and illicit drugs. For young adults aged 18 to 25, rates of substance dependence or abuse were 13.5 percent for alcohol only, 4.0 percent for illicit drugs only, and 4.2 percent for both alcohol and illicit drugs. For adults aged 26 or older, rates of substance dependence or abuse were 5.5 percent for alcohol only, 1.1 percent for illicit drugs only, and 0.7 percent for both alcohol and illicit drugs.