The analysis focused on murder, criminal sexual assault, robbery, and aggravated assault. It also noted that Illinois is one of two States that classify juveniles as individuals younger than age 17. Results revealed that more arrests for violent crime occurred in 1991 than in 1985 across the entire age spectrum, although the percentage of violent crime arrestees younger than age 17 declined during the same period. The percentage of all violent crime arrestees younger than 17 was 17 percent in 1985 and 14 percent in 1991. For ages 17-24, the corresponding percentages were 38 percent and 39 percent, while those for adults over age 24 were 46 percent and 47 percent. The data for all types of violent crime revealed that those ages 17- 24 were more than six times as likely to be arrested for a violent offense in 1991 as individual younger than age 17. Murder arrest rates rose rapidly after age 14, peaked during the late teens and early 20's, and fell to substantially lower levels by the age of 35. In contrast, sexual assault arrest rates began to increase rapidly after age 11 and continued at relatively high levels into the 40's. Figures