Prisons in the US have bigger and bigger populations of non-violent crimes.

There has been a 790 Percent Increase in people put in prison.  About half of them were put in prison for non violent reasons.  Since going to private prisons - the industry has become a real money maker.

http://thinkprogress.org/justice/2013/02/07/1552751/federal-prison-population-spiked-790-percent-since-1980/