In the years following imperialism Nigeria has experienced civil war, political turmoil, military coups, government corruption, and economic collapse. When the British left in 1960 there were elections but no single party won a majority. Two major political parties, the NPC and NCNC, combined and ruled Nigeria together. There were severe conflicts in the early years of Nigerian independence. In 1966 Igbo military officers staged a coup and gained control of the government. Later that year officers from the ethnic group of the Hausa ousted the Igbo military government. In retaliation to the Igbo coup the Hausa not only regained control of the government but also massacred many Igbo civilians. Nigeria remained under martial law. In the late 1960's the Igbo sought autonomy from the Hausa who controlled the government and tried to form a a separate nation known as Biafra. Biafra tried to secede from the rest of Nigeria and started a civil war. This effort was unsuccessful and the Hausa regained control of Biafra. The civil war ended in 1970 and there was a slow return to civilian government. Unsustainable economic growth started by the British led to economic collapse and extreme poverty. Nigeria recovered from economic collapse by beginning to export oil, however the oil industry has created massive wealth inequity and government corruption. Unemployment rates in Nigeria are still high and poverty is still common. There is also currently conflict in Nigeria with Muslim extremist groups who are trying to impose a radical version of Islamic law and government. However the official religion of Nigeria is Christianity. These Muslim groups often perpetrate violent attacks on the rest of Nigeria. For example, there was recently a highly publicized incident where the radical Muslim group Boko Haram kidnapped hundreds of Nigerian school girls. These kidnappings were motivated by the radical Muslim belief that girls should not receive an education.