The OECD has 38 members, and none has joined since 2021
The Organisation for Economic Co-operation and Development is a club of countries that compare their economic policies and publish shared statistics. On 1 October 2026 it had 38 members. It was set up in 1961 to replace the body that had run Marshall Plan aid in Europe, and its twenty founders came from Europe and North America. It has since spread to the Pacific, Latin America and central Europe. Eight more countries are negotiating to join, and three were close to finishing in 2026, but none had become a member by 1 October 2026. The European Union takes part in the OECD's work without being a member.
Name them all first. Then try the harder part: name them in five groups, by when they joined.