Bangladesh followed by 86.6 percent of the population. The country is home to most Bengali Muslims, the second-largest ethnic group in the Muslim world. Most Bangladeshi Muslims are Sunni, followed by Shia and Ahmadiya. About four percent are non-denominational Muslims. Bangladesh has the fourth-largest Muslim population in the world, and is the third-largest Muslim-majority country (after Indonesia and Pakistan). Sufism has a lengthy heritage in the region. The largest gathering of Muslims in Bangladesh is the Bishwa Ijtema, held annually by the Tablighi Jamaat. The Ijtema is the second-largest Muslim congregation in the world, after the Hajj. Hinduism is followed by
Muslim world boundaries of the Muslim world. The Open Doors USA organization, in its 2012 survey of countries around the world that persecute Christians, listed 37 members of the Muslim world amongst the top 50 countries where Christians face the most severe persecution. 9 of the top 10 countries are Islamic-majority states. As the Muslim world came into contact with secular ideals, societies responded in different ways. Some Muslim-majority countries are secular. Azerbaijan became the first secular republic in the Muslim world, between 1918 and 1920, before it was incorporated into the Soviet Union. Turkey has been governed as a secular state