According to the Federal Bureau of Prisons, there are 148 Federal prisons--facilities located throughout the United States. The Bureau operates institutions at five different security levels. As of September 2013, the total Federal inmate population is 211,150. In 1989, the Federal prison population was only 58,000. The massive increase in the Federal prison population is attributed to the "War on Drugs" and tightening restrictions against illegal immigration. The already-taxed Bureau of Prisons in 2012 swelled to 39 percent above capacity. Overcrowded prisons have decreased rehabilitation and increased institution violence. Federal offenses range from drug charges to national security.