Buried in a stupid NCAA research blast about substance vice among young people and college athletes' relative virtues, you'll find this chart, which is hilarious.
The numbers come from an anonymous NCAA survey, but almost definitely come in on the low end, since college athletes usually aren't anxious to tell their schools they're doing drugs, even on anonymous surveys administered by the NCAA. There are some other charts from the survey floating around, like this one, which shows the lacrosse managing to be the one sport that's maintained consistent growth in cocaine use since 2005:
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