Baghdad's population was estimated at 7.22 million in 2015. The city historically had a predominantly Sunni population, but by the early 21st century around 52% of the city's population were Iraqi Shi'ites. At the beginning of the 21st century, some 1.5 million people migrated to Baghdad. Sunni Muslims make up 45% of Iraq's population and they are still a majority in west and north Iraq. As early as 2003, about 20 percent of the population of the city was the result of mixed marriages between Shi'ites and Sunnis. Following the sectarian violence in Iraq between the Sunni and Shia militia groups during the U.S. occupation of Iraq. The Iraqi Civil War following ISIS' invasion in 2014 caused hundreds of thousands of Iraqi internally displaced people to flee to the city. The city has Shia, Sunni, Assyrian/Chaldean/Syriacs, Armenians and mixed neighborhoods. The city was also home to a large Jewish community and regularly visited by Sikh pilgrims.