Today there are 9 million people living in Baghdad, among them a million Anbari people in the city and suburbs; their origins are the people of the Al-Anbar tribes that have moved to Baghdad during the past 500 years and their recent migrations there during the 1920s and 1930s. Half of the residents in Anbar are living on the banks of the Euphrates River outside cities and the towns, there were between 1.9 million and 2 million inhabitants in the districts of Al Anbar. The largest cities are Ramadi (pop. 900,000) and Fallujah (700,000). According to UN estimate in 2003 the population of Al Anbar is 1,230,169. There are no precise estimates of the population which include all of the cities and towns and villages in Anbar. According to a 2003 estimate by the NGO Coordination Committee in Iraq, the population was 1,230,140. It is estimated that around 90 percent of Anbar's inhabitants are adherents of the Sunni branch of Islam. The remaining ten percent are either Christians or other minorities. The governorate contains a lot of mosques, monuments, and shrines. List of governors in post-Baathist Iraq:  The geographic challenge of the Anbar Governorate is demonstrated by two contrasting facts: while it is Iraq's largest governorate, it also is its most sparsely populated. For a governorate that is approximately the size of Bangladesh, it is home to fewer than 1.8 million Iraqis. Most of the population lives in the major cities, like Ramadi and Fallujah, and almost everyone else lives within a short distance of the Euphrates River that snakes from Baghdad to the Syrian border near Al-Qa'im. Its strategic challenge was demonstrated, in part, by casualty statistics. During the first four years of Operation Iraqi Freedom (OIF), the Anbar Province was the deadliest province for American service members, claiming approximately one-third of American fatalities. The Anbar Province was the Sunni stronghold that had long provided Saddam Hussein with the support he needed to remain in power. During the early years of Operation Iraqi Freedom, it provided an important base for Al Qaeda and insurgent operations. Part of its significance came from the fact that the Western Euphrates River Valley served as an important infiltration route for foreign fighters headed to Iraq's heartland. "The New York Times" compared this region to the Vietnam War's Ho Chi Minh Trail, as foreign fighters and insurgents used the river valley to move in relative safety from the Syrian border to cities like Baghdad, Ramadi and Fallujah.