"At yearend 2006, 23 States and the Federal system operated at more than 100% of their highest capacity. Seventeen States operated at between 90% and 99% of their highest capacity. The Federal prison system was operating at 37% above its rated capacity at yearend 2006.
"By comparison, in 1995 States operated at 114% of their highest capacity and 125% of their lowest reported capacity. The Federal system was operating at 26% over reported capacity in 1995."
Sabol, William J., PhD, Couture, Heather, and Harrison, Paige M., Bureau of Justice Statistics, Prisoners in 2006 (Washington, DC: US Department of Justice, December 2007), NCJ219416, pp. 5-6.