The Organization of the Petroleum Exporting Countries
is an intergovernmental organization of 13 nations. Founded on 14 September 1960 in Baghdad by the first five members, it has since 1965 been headquartered in Vienna, Austria, although Austria is not an OPEC member state. As of September 2018, the 13 member countries accounted for an estimated 44 percent of global oil production and 81.5 percent of the world's "proven" oil reserves, giving OPEC a major influence on global oil prices that were previously determined by the so-called "Seven Sisters" grouping of multinational oil companies. A larger group called OPEC+ was formed in late 2016, to have more control on global crude oil market. The demand for OPEC oil has fallen to a 30-year low in second quarter of 2020.