First-time marijuana use among college students is at the highest level in three decades, a new study finds.

Among 19- to 22-year-olds who had never used marijuana by 12th grade, those who go to college are 51 percent more likely to try the drug than those who do not attend college, HealthDay reports.

“These days if you’re in college, about 1 in 5 students will become first-time marijuana users. If you don’t go to college, your chances are more like 1 in 10,” said lead researcher Richard Miech of the University of Michigan’s Institute for Social Research.

The findings appear in the American Journal of Public Health.