California's prison population drops dramatically

California Department of Corrections and Rehabilitation / EPA

In 2006 prisoners at Solano Prison in Vacaville had to sleep in common areas due to overcrowding issues.

For years California's prison population has been notoriously large: some say the biggest in the world (with the sometimes exception of the U.S.'s federal prison system, which currently stands at 217,859). Reaching a peak of170,794 in 2006, California's prison population has reached a 17-year low of 135,519.

Which means that Texas, with 154,000 inmates, is now on top. 

California's inmate decline is primarily the result of changes to the state's parole system and prison realignment, which have both reduced the influx of inmates to state prison.

In 2011, the US Supreme Court upheld an order demanding California drastically reduce its prison population or else build more prisons to relieve overcrowding.