In addition to counties and municipalities, states often create special purpose authorities, such as school districts and districts for fire protection, sanitary sewer service, public transportation, public libraries, public parks or forests, or water resource management. Such special purpose districts may encompass areas in multiple municipalities or counties. According to the US Census Bureau's data collected in 2012, there were 89,004 local government units in the United States. This data shows a decline from 89,476 units since the last census of local governments performed in 2007.