Since 1975, the Monitoring the Future Study has measured the extent of drug abuse among high school seniors. In 1991, the study began also surveying 8th- and 10th-grade students, providing estimates of drug use among a younger population. Among the graduating class of 1996, 50.8 percent of students had used an illicit drug by the time they reached their senior year of high school, continuing an upward trend from 40.7 percent in 1992 but still far below the peak of 65.6 percent in 1981. Use of any illicit drug in the preceding year (annual use) by seniors increased from 27.1 percent in 1992 to 40.2 percent in 1996 after steadily declining from a peak of 54.2 percent in 1979. The percentage of seniors who had used an illicit drug within the preceding month (current use) increased from 14.4 percent in 1992 to 24.6 percent in 1996.