Ethiopia is a composite of more than 70 ethnic groups. The Oromo (Galla) group represents approximately 40% of the population and is concentrated primarily in the southern half of the nation. The Amhara and Tigrean groups constitute approximately 32% of the population and have traditionally been dominant politically. The Sidamo of the southern foothills and savanna regions account for 9%, while the Shankella make up about 6% of the population and reside on the western frontier. The Somali (6%) and Afar (4%) inhabit the arid regions of the east and southeast. Nilotic peoples live in the west and southwest along the Sudan border. The Gurage account for 2% of the population; the remaining 1% is made up of other groups. The Falasha (who call themselves Beta Israel, and are popularly known as "black Jews") live in the mountains of Simen; they were reportedly the victims of economic discrimination before the 1974 revolution and of religious and cultural persecution after that time. Some 14,000 were secretly flown to Israel via the Sudan in 1984–85. About 14,000 more were flown out of Addis Ababa in 1991. Another 4,500 are believed to remain. The Beja of the northernmost region, the Agau of the central plateaus, and the Sidamo of the southern foothills and savanna regions are the remnants of the earliest known groups to have occupied Ethiopia.