<P> As of May 2017, OPEC has 14 member countries: six in the Middle East (Western Asia), six in Africa, and two in South America . According to the US Energy Information Administration, OPEC's combined rate of oil production (including gas condensate) represented 44 percent of the world's total in 2016, and OPEC accounted for 73 percent of the world's "proven" oil reserves, including 48 percent from just the six Middle Eastern members: </P> <P> Approval of a new member country requires agreement by three - quarters of OPEC's existing members, including all five of the founders . In October 2015, Sudan formally submitted an application to join, but it is not yet a member . </P> <Table> <Tr> <Th> Country </Th> <Th> Region </Th> <Th> Membership Years </Th> <Th> Population (2016 est .) </Th> <Th> Area (km) </Th> <Th> Oil Production (bbl / day, 2016) </Th> <Th> Proven Reserves (bbl, 2016) </Th> </Tr> <Tr> <Td> Algeria </Td> <Td> North Africa </Td> <Td> 1969--</Td> <Td> 40,606,052 </Td> <Td> 2,381,740 </Td> <Td> 1,348,361 </Td> <Td> 12,200,000,000 </Td> </Tr> <Tr> <Td> Angola </Td> <Td> Southern Africa </Td> <Td> 2007--</Td> <Td> 28,813,463 </Td> <Td> 1,246,700 </Td> <Td> 1,769,615 </Td> <Td> 8,423,000,000 </Td> </Tr> <Tr> <Td> Ecuador </Td> <Td> Americas </Td> <Td> 1973--1992, 2007--</Td> <Td> 16,385,068 </Td> <Td> 283,560 </Td> <Td> 548,421 </Td> <Td> 8,273,000,000 </Td> </Tr> <Tr> <Td> Equatorial Guinea </Td> <Td> Western Africa </Td> <Td> 2017--</Td> <Td> 1,221,490 </Td> <Td> 28,051 </Td> <Td> 227,000 </Td> <Td> 1,100,000,000 </Td> </Tr> <Tr> <Td> Gabon </Td> <Td> Western Africa </Td> <Td> 1975--1995, 2016--</Td> <Td> 1,979,786 </Td> <Td> 267,667 </Td> <Td> 210,820 </Td> <Td> 2,000,000,000 </Td> </Tr> <Tr> <Td> Iran </Td> <Td> Middle East </Td> <Td> 1960--</Td> <Td> 80,277,428 </Td> <Td> 1,648,000 </Td> <Td> 3,990,956 </Td> <Td> 157,530,000,000 </Td> </Tr> <Tr> <Td> Iraq </Td> <Td> Middle East </Td> <Td> 1960--</Td> <Td> 37,202,572 </Td> <Td> 437,072 </Td> <Td> 4,451,516 </Td> <Td> 143,069,000,000 </Td> </Tr> <Tr> <Td> Kuwait </Td> <Td> Middle East </Td> <Td> 1960--</Td> <Td> 4,052,584 </Td> <Td> 17,820 </Td> <Td> 2,923,825 </Td> <Td> 101,500,000,000 </Td> </Tr> <Tr> <Td> Libya </Td> <Td> North Africa </Td> <Td> 1962--</Td> <Td> 6,293,253 </Td> <Td> 1,759,540 </Td> <Td> 384,686 </Td> <Td> 48,363,000,000 </Td> </Tr> <Tr> <Td> Nigeria </Td> <Td> Western Africa </Td> <Td> 1971--</Td> <Td> 185,989,640 </Td> <Td> 923,768 </Td> <Td> 1,999,885 </Td> <Td> 37,070,000,000 </Td> </Tr> <Tr> <Td> Qatar </Td> <Td> Middle East </Td> <Td> 1961--</Td> <Td> 2,569,804 </Td> <Td> 11,437 </Td> <Td> 1,522,902 </Td> <Td> 25,244,000,000 </Td> </Tr> <Tr> <Td> Saudi Arabia </Td> <Td> Middle East </Td> <Td> 1960--</Td> <Td> 32,275,687 </Td> <Td> 2,149,690 </Td> <Td> 10,460,710 </Td> <Td> 266,578,000,000 </Td> </Tr> <Tr> <Td> United Arab Emirates </Td> <Td> Middle East </Td> <Td> 1967--</Td> <Td> 9,269,612 </Td> <Td> 83,600 </Td> <Td> 3,106,077 </Td> <Td> 97,800,000,000 </Td> </Tr> <Tr> <Td> Venezuela </Td> <Td> Americas </Td> <Td> 1960--</Td> <Td> 31,568,179 </Td> <Td> 912,050 </Td> <Td> 2,276,967 </Td> <Td> 299,953,000,000 </Td> </Tr> <Tr> <Th_colspan="3"> OPEC Total </Th> <Th> 478,498,000 </Th> <Th> 12,150,695 </Th> <Th> 35,221,740 </Th> <Th> 1,209,103,000,000 </Th> </Tr> <Tr> <Th_colspan="3"> World Total </Th> <Th> 7,588,065,000 </Th> <Th> 510,072,000 </Th> <Th> 80,622,287 </Th> <Th> 1,650,585,000,000 </Th> </Tr> <Tr> <Th_colspan="3"> OPEC Percent </Th> <Th> 6% </Th> <Th> 2% </Th> <Th> 44% </Th> <Th> 73% </Th> </Tr> </Table> <Tr> <Th> Country </Th> <Th> Region </Th> <Th> Membership Years </Th> <Th> Population (2016 est .) </Th> <Th> Area (km) </Th> <Th> Oil Production (bbl / day, 2016) </Th> <Th> Proven Reserves (bbl, 2016) </Th> </Tr>

When did nigeria become a member of opec