Better yet, we stand to save a few dollars as a result. Over the last three decades, the federal prison population has grown by almost 800 percent, so that it now contains some 219,000 inmates, about half of whom are there for drug crime. And, as our penitentiaries have gotten fuller, running them has become more expensive. From 2000 to 2012, the federal prison system’s budget grew 79 percent, to more than $6.5 billion, as shown in the graph below courtesy of theUrban Institute.
http://m.theatlantic.com/business/archive/2013/08/heres-how-much-it-costs-the-feds-to-lock-up-219-000-people/278586/