The establishment of the Democratic Republic of Afghanistan in 1978 and the Soviet invasion of the country the following year disrupted the country's population patterns. Civil war and the destruction of towns and villages caused mass movements of people in two major directions--emigration, mainly to Pakistan and Iran, or escape to the relative safety of the capital city, Kabul. By some estimates almost 5,000,000 people escaped to Pakistan and some 1,850,000 to Iran; the population of Kabul is estimated to have doubled in size. Kabul has grown to encompass almost half of the urban population of the country. Afghanistan's population is mainly rural; almost half of the population is under 15 years of age. Life expectancy is less than 45 years. According to some estimation the population of Afghanistan has risen to 20 million in recent years. There is estimated 2.5 million Afghan still live in Pakistan as refugees and according to some (unconfirmed( report about 3.5 million in Iran.