Peshawar has hosted Afghan refugees since the start of the Afghan civil war in 1978, though the rate of migration drastically increased following the Soviet invasion of Afghanistan in 1979. By 1980, 100,000 refugees a month were entering the province, with 25% of all refugees living in Peshawar district in 1981. The arrival of large numbers of Afghan refugees strained Peshawar's infrastructure, and drastically altered the city's demography. During the 1988 national elections, an estimated 100,000 Afghans refugees were illegally registered to vote in Peshawar.