A recent University of Michigan study found that one in 10 high school seniors say they’ve vaped marijuana in the past year. The vape caveat is an important one. Richard Miech, the researcher in charge of the study, said the number of teens that are vaping the drug is much higher than he expected, The Chicago Tribune reports.

Over the past few years, teen marijuana use has been flat. However, in this year’s study, use of the drug is up 1% in teens, with 25% of respondents saying they had vaped, smoked, or eaten marijuana over the past year.

The study looked at 45,000 students in grades eight, 10, and 12.

While the use of drugs like cocaine and heroin have reached their lowest levels in 43 years, marijuana use in teens has even surpassed that of cigarette smoking. Five percent of teens said they had smoked cigarettes in the past 30 days, while 15% said they had used marijuana.

While vaping isn’t the only way teens are using marijuana, it is a popular one. Twenty percent of teens said that they only consumed marijuana through vaping.