Question for you: What percentage of the US population do you think regularly (say, once a month or more) consumes hard drugs? Include prescription painkillers

Question for you: What percentage of the US population do you think regularly (say, once a month or more) consumes hard drugs? Include prescription painkillers and amphetamines in this count, even if they are prescribed by doctors. I'll bet it's not too far away from 20% already.