The Organisation for Economic Co-operation and Development (OECD; , OCDE) is an intergovernmental organisation with 38 member countries, founded in 1961 to stimulate economic progress and world trade. It is a forum whose member countries describe themselves as committed to democracy and the market economy, providing a platform to compare policy experiences, seek answers to common problems, identify good practices, and coordinate domestic and international policies of its members. The majority of OECD members are high-income economies with a very high Human Development Index (HDI), and are regarded as developed countries. Their collective population is 1.38 billion. , the OECD member countries collectively comprised 62.2% of global nominal GDP (US$49.6 trillion) and 42.8% of global GDP (Int$54.2 trillion) at purchasing power parity. The OECD is an official United Nations observer. In April 1948, the Organisation for European Economic Co-operation (OEEC), was established to help administer the Marshall Plan, which was rejected by both the Soviet Union and its satellite states. This would be achieved by allocating the United States' financial aid and implementing economic programs for the reconstruction of Europe after World War II. Only Western European states were members of the OEEC. Its Secretaries-General were the Frenchmen Robert Marjolin (1948–1955) and René Sergent (1955–1960). On 14 December 1960, the OEEC was reformed into the Organisation for Economic Co-operation and Development, coming into force in late September 1961, and the membership was extended to non-European states, the USA and Canada. The OECD's headquarters are at the Château de la Muette in Paris, France. The OECD is funded by contributions from member countries at varying rates and had a total budget of € 386 million in 2019, and is recognised as a highly influential publisher of mostly economic data through publications as well as annual evaluations and rankings of member countries. History Organisation for European Economic Co-operation The Organisation for European Economic Co-operation (OEEC) was formed in 1948 to administer American and Canadian aid in the framework of the Marshall Plan for the reconstruction of Europe after World War II. Similar reconstruction aid was sent to the war-torn Republic of China and post-war Korea, under the title of Official Development Assistance (ODA), provided by the OEEC's Development Assistance Committee (DAC), which Korea joined in 2010. The organisation began its operations on 16 April 1948, originating from the work done by the Committee of European Economic Co-operation in 1947 in preparation for