Haha. It's a shame that these days weed smokers tend to be foolish idiots. I think it makes cannabis look bad and has no doubt actually held the legalization process back as people see cannabis smokers as the cliches that they're usually portrayed as.
In that case more than half of the US population (probably with the exception of the religious nuts) will be foolish idiots, by your definition. According to an opinion poll by Gallup, around 38% of the American population (and probably more than half of the American males) have tried smoking weed at least once in their life.
http://www.gallup.com/poll/163835/tried-marijuana-little-changed-80s.aspx
Now imagine 100 million Americans going to the jail as a part of the war on drugs.
There's a big difference between trying weed once or twice and habitual stoners who think weed is the magic medicine that can cure cancer and every other form of disease and maladies.