How many people are in prison for marijuana as of 2010?

Answer 1

1 in 150 inmates

The answer above is incorrect by a long shot. The Dept. of Justice reported 1 in 8 inmates are in for pot, costing us over $1billion/year. In 2007 there were 1,841,182 drug arrests and 47.4% were for marijuana (that's 872,720) and 89% were for possession.