In exchange. the recipients agree to pro. vide primary health care at designated sites in health manpower shortage areas for a speci. fied period of time. The corps is 20 years old this year. Over the past two decades. the corps has placed over 10.000 physicians and other health professionals in rural and urban communities that have been left unserved by the market. It has been a critical source of staffing for the community and migrant health center programs as well as the Indian Health Service. As we enter the 1990s. the corps faces a major challenge. According to the Department. there are about 12.5 million Americans living in over 1900 rural and urban areas with a shortage of primary care practitioners.