As a sanity check if you where 15 in 1960 your ~69.
PS: Though, in an informal survey's my 14-15 year old classmates in the 1990's over 90% said they had used pot in the last year. So their numbers might be off.
Yeah sure but statistically it is not significant. There is a two year chinese kid that smokes 2 packs a day, but that does not mean a significant number of 2 year old kids smoke.
Also if 14% of people smoke pot that means 80% of all house household smoke pot and it is NOT true.
My point is it's a high variance statistic which is hard to control for.
If population A = 95%, Population B = 30%, and Population C = 1% then it becomes vary important to get the correct ratio of populations A, B, and C. And correctly sampling culturally diverse populations in the same geographic area is vary difficult. Something as simple as a phone screen is unlikely to work due to things like % of population in prison or number of phone numbers in a household. Even block by block analysis can fail with transient populations as it's easy to introduce bias by counting someone twice or not at all.
According to this 38% of those surveyed and 17% of those over 65 admit to trying pot. http://www.gallup.com/poll/163835/tried-marijuana-little-cha... Though only 7% of those surveyed where willing to say they currently smoked.
As a sanity check if you where 15 in 1960 your ~69.
PS: Though, in an informal survey's my 14-15 year old classmates in the 1990's over 90% said they had used pot in the last year. So their numbers might be off.