The United States is a federal republic of 50 states, a federal district, five territories and several uninhabited island possessions. It is the world's oldest surviving federation. It is a federal republic and a representative democracy "in which majority rule is tempered by minority rights protected by law." Since 2015, the U.S. has ranked 25th on the Democracy Index, and is described as a "flawed democracy". On Transparency International's 2019 Corruption Perceptions Index, its public sector position deteriorated from a score of 76 in 2015 to 69 in 2019.