American teens’ use of drugs, alcohol and tobacco has declined to the lowest rate since the 1990s, according to an annual nationwide study.

The Monitoring the Future study found marijuana use declined this year among 8th- and 10th graders, but remains flat among 12th graders, USA Today reports.

This year, 37.3 percent of 12th graders said they had been drunk at least once, down from 53.2 percent in 2001. Only 1.8 percent of 12th graders said they smoke a half pack of cigarettes or more daily, down from almost 11 percent in 1991. E-cigarette use decreased from 16 percent last year to 12 percent this year among high school seniors.

Use of prescription opioid painkillers fell among high school seniors, as did use of illicit drugs other than marijuana.