The above graph shows four different series for OPEC production. The EIA Table 1.4 and IEA series are "all liquids" (that is, including NGLs - Natural Gas Liquids). The EIA Table 1.1 is Crude+Condensate, and the OPEC MOMR series is crude only.
Note that during the period of this graph (since 2000), there have been membership changes. The history is as follows:
The Organization of the Petroleum Exporting Countries (OPEC) was founded in Baghdad, Iraq, with the signing of an agreement in September 1960 by five countries namely Islamic Republic of Iran, Iraq, Kuwait, Saudi Arabia and Venezuela. They were to become the Founder Members of the Organization.The IEA series reflects these changes, but the EIA series seems to have been reworked backwards to be the production of the current OPEC membership, rather than production of the membership at the time.
These countries were later joined by Qatar (1961), Indonesia (1962), Socialist People’s Libyan Arab Jamahiriya (1962), the United Arab Emirates (1967), Algeria (1969), Nigeria (1971), Ecuador (1973), Gabon (1975) and Angola (2007).
From December 1992 until October 2007, Ecuador suspended its membership. Gabon terminated its membership in 1995. Indonesia suspended its membership effective January 2009.
The questions of most interest at present are how far from the previous peak production we are now, and how soon we will reach that again. All series show increases since the depths of the recession, and we are 1.5-2mbd from the peak in each case (accounting for the disappearance of about 850kbd of Indonesian production from the OPEC total in the IEA series since the 2008 peak of production).
Once we reach that peak, the main remaining question will be how much of Saudi Arabia's new capacity has been offset by losses in the big old fields - particularly the northern part of Ghawar.