No wonder states like California and others experienced a boom in prison construction beginning in the 1980s.

According to statistics compiled by The Sentencing Project, a nonprofit dedicated to prison reform, the total number of people in jails and prisons for violating drug laws soared from 41,000 in 1980 to 507,000 by 2010.

During this same 30-year period, the overall prison and jail population more than quadrupled, from 502,886 to 2,266,832 inmates. The United States leads the world in per capita incarceration at 743 per 100,000, ahead of Rwanda (c595) and Russia (568).

By 2010, just over half (51%) of all inmates in federal prisons were convicted of drug-related crimes. For state prisons the percentage is much smaller, 17.8% (violent offenders make up the largest share in these prisons, 53.2%).