The great majority (90%) of the Sa'udis have a common Arabian ancestry, and the population is homogeneous in religion and language. Divisions are based mainly on tribal affiliation or descent, the primary distinction being between groups with a tradition of being sedentary agriculturalists or traders, and the Bedouins, who have a tradition of nomadic pastoralism. The two groups traditionally have been antagonistic. There has been some loosening of tribal ties, however, caused by rapid economic development. Afro-Asians account for the remaining 10% of the population. Admixtures of Turks, Iranians, Indonesians, Pakistanis, Indians, various African groups, and other non-Arab Muslim peoples appear in the Hijaz, mostly descendants of pilgrims to Mecca.