Former U.S.S.R. The Union of Soviet Socialist Republics (U.S.S.R.), listed here as Former U.S.S.R., disbanded on December 26, 1991 into fifteen successor countries: Armenia, Azerbaijan, Belarus, Estonia, Georgia, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Moldova, Russia, Tajikistan, Turkmenistan, Ukraine, and Uzbekistan. Crude oil and natural gas plant liquids production data for the Former U.S.S.R. are reported for the years 1970-1991. The term Former U.S.S.R. is used in the tables in the Oil Balance section as a purely geographical expression to refer to the aggregate data for the fifteen successor countries.

International Energy Agency (IEA) countries are: Australia, Austria, Belgium, Canada, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan, Luxembourg, Netherlands, New Zealand, Norway, Portugal, Slovakia, South Korea, Spain, Sweden, Switzerland, Turkey, United Kingdom, and United States.

Organization for Economic Cooperation and Development (OECD) countries are: Australia, Austria, Belgium, Canada, Chile, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Luxembourg, Mexico, Netherlands, New Zealand, Norway, Poland, Portugal, Slovakia, South Korea, Spain, Sweden, Switzerland, Turkey, United Kingdom, and United States. Data for Total OECD include the United States Territories (Guam, Puerto Rico, and the U.S. Virgin Islands) for all years and the Hawaiian Trade Zone for 1970-1986.

OECD Europe countries are: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland, Turkey, and United Kingdom.

Organization of Arab Petroleum Exporting Countries (OAPEC) are: Algeria, Bahrain, Egypt, Iraq, Kuwait, Libya, Qatar, Saudi Arabia, Syria, Tunisia, and the United Arab Emirates. In April 1979, Egypt was suspended from OAPEC membership. In May 1989, Egypt rejoined OAPEC. For consistency, Egypt is included in the historical data series of the OAPEC totals.

Organization of the Petroleum Exporting Countries (OPEC) are: Algeria, Angola, Ecuador, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, the United Arab Emirates, and Venezuela. On December 31, 1994, Gabon withdrew its membership in OPEC and, on January 1, 2009, Indonesia suspended its membership in OPEC. For consistency, Gabon and Indonesia are excluded in the historical data series of OPEC totals.

Persian (Arabian) Gulf countries are: Bahrain, Iran, Iraq, Kuwait, Qatar, Saudi Arabia, and the United Arab Emirates.