"The increase in justice expenditures over nearly 20 years reflects the expansion of the Nation's justice system. For example, in 1982 the justice system employed approximately 1.27 million persons; in 2003 it reached over 2.3 million.
"Police protection
"One indicator of police workload, the FBI's arrest estimates for State and local police agencies, grew from 12 million in 1982 to an estimated 13.6 million in 2003. The number of employees in police protection increased from approximately 724,000 to over 1.1 million.
"Judicial and legal
"The judicial and legal workload, including civil and criminal cases, prosecutor functions, and public defender services, also expanded during this period. Cases of all kinds (criminal, civil, domestic, juvenile, and traffic) filed in the nearly 16,000 general and limited jurisdiction State courts went from about 86 million to 100 million in the 16-year period, 1987-2003. The total of judicial and legal employees grew about 101% to over 494,000 persons in 2003.
"Corrections
"The total number of State and Federal inmates grew from 403,000 in 1982 to over 1.4 million in 2003. The number of local jail inmates more than tripled from approximately 207,000 in 1982 to over 691,000 in 2003. Adults on probation increased from over 1.4 million to about 4.1 million persons. Overall, corrections employment more than doubled from nearly 300,000 to over 748,000 during this same period."

Source

Hughes, Kristen A., "Justice Expenditure and Employment in the United States, 2003" (Washington, DC: US Dept. of Justice, Bureau of Justice Statistics, April 2006), NCJ212260, p. 7.
http://www.bjs.gov/content/pu…