In 1990, the total economic cost estimates varied widely for each substance, with alcohol and nicotine inflicting the greatest direct and indirect costs (see Figure 2.3). Nicotine addiction comprised almost three-fourths (74 percent) of the total substance-related direct costs of $52.8 billion. Alcohol accounted for 20 percent, and illegal drugs for the remaining 6 percent. In regard to morbidity costs, alcohol constituted 72 percent of the $51 billion spent while nicotine made up 55 percent of the $82.6 billion spent on mortality costs. Illegal drugs made up 17 percent of the morbidity costs, 4 percent of the mortality costs, but 75 percent of the $61.8 billion for other related costs (other related costs are not available for nicotine).