http://www.smallarmssurveysudan.org/fileadmin/docs/working-papers/HSBA-WP-22-The-Other-War-Inter-Arab-Conflict-in-Darfur.pdf, "Although the most recent census, conducted in 2008, puts Darfur’s popu- lation at 7.5 million, the NCP of President Omar al Bashir insisted that tribe and religion be omitted from the database, reportedly for fear that Sudan would no longer be defined as an Arab, Islamic state. Estimates of the Arab population of Darfur range from 30 per cent, based on the census of 1956, to the 70 per cent claimed by Arab tribal leaders in a letter to United Nations Secretary-General Ban Ki-moon in September 2007. Given that many Arabs from Chad have settled in Darfur in the last several decades, and that the rate of migration to Sudan’s more developed centre is higher among non-Arabs, who are less dependent on pastoralism, a figure of 40 per cent is probably closer to the mark."
