Actually, there is evidence that most do not, because Marijuana usage is only 15-17% among all adults, and 20% for ages 18-29. It's even lower for ages 30-49.
I bet blacks/African Americans are a lot higher, but I don't know the stats on that. So yeah, the NFL might be higher based on racial demographics (which doesn't apply to Josh), but the NFL is also full of health conscious individuals who would never smoke anything.