Five of the state's counties are wholly within the boundaries of sovereign Indian reservations. Because of the limitations of climate and land, and isolation from urban areas with more employment opportunities, living standards on many South Dakota reservations are often far below the national average; Ziebach County ranked as the poorest county in the nation in 2009. The unemployment rate in Fort Thompson, on the Crow Creek Reservation, is 70%, and 21% of households lack plumbing or basic kitchen appliances. A 1995 study by the U.S. Census Bureau found 58% of homes on the Pine Ridge Indian Reservation did not have a telephone. The reservations' isolation also inhibits their ability to generate revenue from gaming casinos, an avenue that has proved profitable for many tribes closer to urban centers.