Although the data are not absolutely reliable, the government estimates that 76 % of the people are Arab; 19 % are Kurds; while Turkomans, Assyrians, Armenians, and other comparatively small groups make up the rest. All but a small %age adhere to Islam. The Islamic component is split into two main sects, Sunni and Shia, with the Shias by far the majority. Officially the government sets the number of Shias at 55 %. In the 1980s knowledgeable observers began to question this figure, regarding it as low. Because the government does not promote birth control and the Shias, the least affluent in society, have traditionally had the highest birthrate, a more reasonable estimate of their numbers would seem to be between 60 and 65 %. All but a few of the around 3,088,000 Kurds are Sunni, and thus the Sunni Arabs--who historically have been the dominant religious and ethnic group-- constitute a decided minority vis-á-vis the Shia majority. s

The ancient Semitic peoples of Iraq, the Babylonians and Assyrians, and the non-Semitic Sumerians were long ago assimilated by successive waves of immigrants. The Arab conquests of the 7th century brought about the Arabization of central and southern Iraq. A mixed population of Kurds and Arabs inhabit a transition zone between these and Iraqi Kurdistan. More than three-fourths of Iraq's people are Arabs, about a fifth are Kurds, and the remainder consists of small minority groups.