Marijuana Use by U.S. Teens Has Jumped 10-fold Since 1990s

The study looked at 1991-2017 U.S. federal health data on more than 200,000 high school students. It found that the number who said they'd used pot at least once over the past month rose 10-fold -- from 0.6% in 1991 to 6.3% by 2017.