[robertpaulsen]

I define a marijuana "user" as one who smokes marijuana at least once a month. "At least once a year" don't hack it; "ever used" is a useless statistic.

Tracking those who use marijuana at least once per month, we find that the number of users dropped by over 60% since 1979, and remained flat for the last ten years (with the exception of the last year or two).

I call that a success. You say it's not working.

[green iguana]

I define a marijuana "user" as one who smokes marijuana at least once a month.

That's nice. Your data doesn't tell you this though. Someone who smoked pot in the last month is not necessarily someone who smokes pot at least once a month.

"ever used" is a useless statistic

Hardly useless - it tells us the percentage of people in the US who have used an illicit drug. Not terribly relevant in a conversation about current users only, but hardly useless. It just depends on what point you're trying to make.

[Know your rights]

the number of users dropped by over 60% since 1979, and remained flat for the last ten years (with the exception of the last year or two).

I call that a success.

This decline may have nothing to do with the WOD, as alcohol use declined during the same period. ("the per capita consumption of alcohol has continued to decline since 1980 among the populace as a whole, and among underage drinkers [...] Since 1980 per capita consumption among college students has slowly decreased mirroring a decrease among adults." - http://www.indiana.edu/~engs/articles/kb.html)