Namibia covers an area of approximately 800,000 square kilometres and has a human population of about 2.1 million. This gives an average density of about 2.6 people per square kilometre. Most of the people of Namibia belong to one of five main ethnic groups of African origin: the Aawambo, Ovaherero, Kavango, Caprivian, and Damara and Nama peoples. The diet of ethnic Namibians comprises a variety of foods such as millet, sorghum, maize, sweet potatoes, groundnuts and fruits. Millet and maize are staple foods. Fruits are mainly wild and indigenous.