The number of high school students who say they used e-cigarettes in the past 30 days has jumped 75 percent since last year, The Wall Street Journal reports. The preliminary data comes from the latest National Youth Tobacco Survey.

About 3 million—or 20 percent—of high school students are vaping, according to the findings. In contrast, last year 1.73 million—or 11.7 percent—used e-cigarettes, according to recently published federal data.

In May, The Wall Street Journal and Mercury Analytics conducted a survey of teens that found almost one-third say they currently vape. More than half of teens who vape say they do it because they like the flavors that e-cigarette liquids come in, and say vaping is fun. More than two-thirds said they think vaping can be part of a “healthy life.”

Earlier this month, Food and Drug Administration Commissioner Scott Gottlieb said youth e-cigarette use in the United States is an epidemic, and announced new steps his agency is taking to prevent youth vaping.