A letter report issued by the Government Accountability Office with an abstract that begins "The Federal Bureau of Investigation's (FBI) Uniform Crime Reporting (UCR) Program, the government's centralized repository for crime data, provides the only available standardized way to track crime levels in border counties over time. However, UCR data lack information on whether reported offenses are attributable to spillover crime, and have other limitations, such as underreporting to police. Also, UCR data cannot be used to identify links with crimes often associated with spillover from Mexico, such as cartel-related drug trafficking. Cognizant of these limitations, GAO's analysis of data for southwest border counties with sufficiently complete data show that, generally, both violent and property crimes were lower in 2011 than in 2004. For example, the violent crime rate in three states' border counties was lower by at least 26 percent in 2011 than in 2004 and in one other state lower by 8 percent in 2011 than in 2005."