extracted in the Niger Delta, with an estimated 38 billion barrels of reserves. The first oil operations in the region began in the 1950s and were undertaken by multinational corporations, which provided Nigeria with necessary technological and financial resources to extract oil. Since 1975, the region has accounted for more than 75% of Nigeria's export earnings. Together oil and natural gas extraction comprise "97 per cent of Nigeria's foreign exchange revenues". Much of the natural gas extracted in oil wells in the delta is immediately burned, or flared, into the air at a rate of approximately 70 million m³per day. This is equivalent to 41% of African natural gas consumption and forms the largest single source of greenhouse gas emissions on the planet. In 2003, about 99% of excess gas was flared in the Niger Delta, although this value has fallen to 11% in 2010. (See also gas flaring volumes). The biggest gas flaring company is the Shell Petroleum Development Company of Nigeria Ltd, a joint venture that is majority owned by the Nigerian government. In Nigeria, "...despite regulations introduced 20 years ago to outlaw the practice, most associated gas is flared, causing local pollution and contributing to climate change." The environmental devastation associated with the industry and the lack of distribution of oil wealth have been the source and/or key aggravating factors of numerous environmental movements and inter-ethnic conflicts in the region, including recent guerrilla activity by MEND. In September 2012 Eland Oil & Gas purchased a 45% interest in OML 40, with its partner Starcrest Energy Nigeria Limited, from the Shell Group. They intend to recommission the existing infrastructure and restart existing wells to re-commence production at an initial gross rate of of oil per day with a target to grow gross production to of oil per day within four years. Oil revenue derivation Oil revenue allocation has been the subject of much contention well before Nigeria gained its independence. Allocations have varied from as much as 50%, owing to the First Republic's high degree of regional autonomy, and as low as 10% during the military dictatorships. * State allocations are based on 5 criteria: equality (equal shares per state), population, social development, land mass, and revenue generation. **The derivation formula refers to the percentage of the revenue oil-producing states retain from taxes on oil and other natural resources produced in the state. World Bank Report Media The