The proportion of older teens who use illicit drugs continued to decline in 2005, according to the latest national survey in this series, the fourth consecutive year of decline among the nationfs 10th- and 12th-grade students. However, the long-term improvements that had been occurring among 8th graders since 1996 appear to have halted this year. The use of marijuana and illicit drugs other than marijuana (taken as a group) showed very modest continuing declines this year among 10th- and 12th-grade students, although none of these one-year decreases reached statistical significance.