Uniform Crime Reporting Program
The Uniform Crime Reporting Program (UCR) is a nationwide, cooperative, statistical effort of more than 17,000 city, county, and state law enforcement agencies voluntarily reporting data on crimes brought to their attention. The program's primary objective is to generate a reliable set of criminal statistics for use in law enforcement administration, operation, and management; however, over the years, its data have become one of the country's leading social indicators. Eight major classifications of crime, known as the crime index, are tracked to gauge fluctuations in the overall volume and rate of crime. These include the violent crimes of murder and nonnegligent manslaughter, forcible rape, robbery, and aggravated assault, and the property crimes of burglary, larceny-theft, motor vehicle theft, and arson.
http://www.fbi.gov/ucr/ucr.htm and related web pages.