The demographics of Sudan include the Sudanese people () and their characteristics, Sudan, including population density, ethnicity, education level, health, economic status, religious affiliations, and other aspects of the population. In Sudan's 1993 census, the population was calculated at 30 million. No comprehensive census has been carried out since that time due to the Second Sudanese Civil War. Estimates of Sudan, including the population of South Sudan, ranged from 37 million (United Nations) to 45 million (CIA). Since the secession of South Sudan in July 2011, the current population of Sudan is estimated to be about million. The population of metropolitan Khartoum (including Khartoum, Omdurman, and Khartoum North) is growing rapidly and ranges from six to seven million, including around two million displaced persons from the southern war zone, as well as western and eastern drought-affected areas. Population overview The majority of the population in Sudan are the indigenous Nubian inhabitants of the Nile Valley. Due to the process of Arabisation common throughout the rest of the Arab world, today Arab culture predominates in Sudan. The majority of ethnic groups of Sudan fall under Arabs, and the minority being Other African ethnic groups such as the Beja, Fur, Nuba, and Fallata. When counted as one people Sudanese Arabs are by far the largest ethnic group in Sudan, however African ethnic groups are a large minority if counted as one group. They are almost entirely Muslim; while the majority speak Sudanese Arabic; some other Arab tribes speak different Arabic dialects like Awadia and Fadnia and Bani Arak tribes who speak Najdi Arabic; Bani Hassan, Al-Ashraf, Kinanah and Rashaida who speak Hejazi Arabic. In addition, Arab tribes like the Baggara and other Darfurians, both who speak Chadian Arabic. Sudanese Arabs of northern and eastern parts descend primarily from migrants from the Arabian Peninsula and some of the pre-existing indigenous populations of Sudan, most predominantly the Nubian people who also share a common history with Egypt. Additionally, a few pre-Islamic Arabian tribes existed in Sudan from earlier migrations into the region from Western Arabia, although most Arabs in Sudan are dated from migrations after the 12th century. The vast majority of Arab tribes in Sudan migrated into the Sudan in the 12th century, intermarried with the indigenous African populations and introduced Islam. Population statistics Achieving good counts of the population is difficult in Sudan, because conducting a census has been difficult due to