Organisation of the Petroleum Exporting Countries (OPEC)

 OPEC is an intergovernmental organization of 13 nations with headquarters in Vienna.

 Algeria, Angola, Ecuador, Gabon, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, United Arab Emirates, and Venezuela are its members.

 The 13 countries accounted for an estimated 42% of global oil production and 73% of the world's "proven" oil reserves.

OPEC's stated mission is to coordinate and unify the petroleum policies of its member countries and ensure the stabilization of oil markets, in order to have regular supply of petroleum to consumers, a steady income to producers, and a fair return on capital for those investing in the petroleum industry.

 Two-thirds of OPEC's oil production and reserves are in its six Middle Eastern countries that surround the oil-rich Persian Gulf.

 Gabon recently rejoined OPEC.

 The OPEC Conference ordinarily meets at least twice a year and in additional extraordinary sessions when necessary.

 OPEC collaborated with five other international organizations (APEC, Eurostat, IEA, OLADE (es), UNSD) to improve the availability and reliability of oil data.

 They launched the Joint Oil Data Exercise, which in 2005 was joined by IEF and renamed the Joint Organisations Data Initiative (JODI), covering more than 90 percent of the global oil market.

 GECF joined as an eighth partner in 2014, enabling JODI also to cover nearly 90 percent of the global market for natural gas.

 Since 2007, OPEC has published the "World Oil Outlook" (WOO) annually, in which it presents a comprehensive analysis of the global oil industry including medium- and long-term projections for supply and demand.