While teenagers smoking marijuana is nothing new, a fresh report by the federal government says more teens say they’re vaping cannabis more frequently. This is of concern to health experts, considering the thousands of people who have been injured by black market vaping products this year. That’s on top of concerns about what regular cannabis consumption can do to the still-developing young mind. According to the National Institute on Drug Abuse’s Monitoring the Future survey report released this week, the rates of high school seniors vaping marijuana at least once in the past year has more than doubled over the past two years. Nearly 21 percent of surveyed 12th graders report vaping at least once while 10th graders are close behind at 19 percent. About seven percent of eighth graders also report vaping marijuana at least once within the past year. While the report has regularly tracked marijuana and other illicit drug use, this was the first time it measured how many teens vape marijuana daily. It found about 3.5 percent of high school seniors do so and three percent of sophomores do as well.