Africa has a large quantity of natural resources, including diamonds, sugar, salt, gold, iron, cobalt, uranium, copper, bauxite, silver, petroleum, and cocoa beans, but also tropical timber and tropical fruit. Recently discovered oil reserves have increased the importance of the commodity on African economies. Sudan and Nigeria are two of the main oil producers. The United States and European countries took most of the Democratic Republic of the Congo's (DRC) oil production. Oil is provided by both continental and offshore productions. Sudan's oil exports in 2010 are estimated by the United States Department of State at US$9 billion. Five countries dominate Africa's upstream oil production. Together they account for 85% of the continent's oil production and are, in order, from highest to lowest output: Nigeria, Libya, Algeria, Egypt and Angola. Other African oil producing countries are Gabon, the DRC, Cameroon, Tunisia, Equatorial Guinea, the Republic of the Congo, Ivory Coast, and more recently, Ghana. Exploration is taking place in a number of other countries that aim to increase their output or become first-time producers. Included in this list are Chad, Sudan, Namibia, South Africa, and Madagascar, whilst Mozambique and Tanzania are potential oil producers. Oil and minerals in Africa Africa has 30% of the remaining mineral resources in the world. 57% of Africa's export earnings comes from hydrocarbons. From 1980 to 2012, proven oil reserves in Africa grew by 150%. Ore resources in Africa are abundant while other continents are beginning to face depletion of resources. The copper belt in Haut-Katanga Province, the diamond mines in Sierra Leone, Angola, and Botswana are well-known for the abundance of mineral resources, albeit with a negative reputation arising from perceptions of their industries' involvement in corrupt practices, and links to violent rebel movements. The RUF (Revolutionary United Front) and the blood diamonds used to supply these rebel factions with arms is one such example. In recent years, exploration activities has grown in West Africa. However, lack of services became a problem for exploration companies. In 2020, West Africa received the third larger budget for exploration projects. From 2009 to 2019, West Africa accounted the major success in gold discoveries. Exploration budgets in Africa fell 10% in 2020, reaching their lower levels in the last four years. Impact of non-African exploitation With a low population density Africa has been colonized by non-African nations from the 16th century, all exploiting African resources to varying degrees.