Ecuador suspended its membership in December 1992, rejoined OPEC in October 2007, but decided to withdraw its membership of OPEC effective 1 January 2020.
Indonesia suspended its membership in January 2009, reactivated it again in January 2016, but decided to suspend its membership once more on 30 November 2016.
Gabon terminated its membership in January 1995. However, it rejoined the Organization in July 2016.
Qatar terminated its membership on 1 January 2019.