As of 2006, the estimated population is 38,329,000, with an estimated growth rate of 2 percent. Population distribution is extremely uneven, with density varying from 1 person per square kilometre (3/mi²) in arid regions to 51 per square kilometre (133/mi²) in the mainland’s well-watered highlands, to 134 per square kilometre (347/mi²) on Zanzibar. More than 80 percent of the population is rural. Dar es Salaam is the largest city and is the commercial capital; Dodoma, located in the centre of Tanzania is the new capital and houses the Union’s Parliament.
The African population consists of more than 120 ethnic groups, of which the Sukuma and Nyamwezi, the Hehe and Bena, the Gogo, the Haya, the Makonde, the Chagga and the Nyakyusa have more than 1 million members. Other groups include the Pare, Sambaa (or Sambala), and Ngoni. The majority of Tanzanians, including such large ethnic groups as the Sukuma and the Nyamwezi, have Bantu origins. Groups of Nilotic or related origin include the nomadic Maasai and the Luo, both of which are found in greater numbers in neighbouring Kenya. The Sandawe and Hadza speak languages of the Khoisan family peculiar to the people of the Kalahari in southern Africa.
The population also includes people of Arab, Indian, and Pakistani origin, and small European and Chinese communities. As of 1994, the Asian community numbered 50,000 on the mainland and 4,000 on Zanzibar. An estimated 70,000 Arabs and 10,000 Europeans resided in Tanzania. The Zanzibar Revolution of 12 January 1964 ended the local Arab dynasty. Thousands of Arabs and Indians in Zanzibar were massacred in riots, and thousands more were detained or fled the island.