First, Health Center Program (HCP) awardees and look-alikes report their patients to the BPHC (in the Uniform Data System) by their ZIP Code of origin. Second, no demographics are available describing ZIP Codes as they are constructed by the U.S. Postal Service. In 2000, the U.S. Census Bureau developed a methodology for providing statistically relevant data that approximates the existing ZIP Codes. These ZIP Code Tabulation Areas (ZCTAs) generally are meant to cover one or more ZIP Codes. By aggregating the health center patients by ZIP Code to the ZCTA level, it is possible to compare the number of health center patients to the population.