Peru engaged in a brief successful conflict with Ecuador in the Paquisha War as a result of territorial dispute between the two countries. After the country experienced chronic inflation, the Peruvian currency, the sol, was replaced by the "Inti" in mid-1985, which itself was replaced by the nuevo sol in July 1991, at which time the new sol had a cumulative value of one billion old soles. The per capita annual income of Peruvians fell to $720 (below the level of 1960) and Peru's GDP dropped 20% at which national reserves were a negative $900 million. The economic turbulence of the time acerbated social tensions in Peru and partly contributed to the rise of violent rebel rural insurgent movements, like Sendero Luminoso (Shining Path) and MRTA, which caused great havoc throughout the country. Concerned about the economy, the increasing terrorist threat from Sendero Luminoso and MRTA, and allegations of official corruption, Alberto Fujimori assumed the presidency in 1990. Fujimori implemented drastic measures that caused inflation to drop from 7,650% in 1990 to 139% in 1991.