Slovenia joined the European Union on 1 May 2004. Slovenia has one Commissioner in the European Commission, and seven Slovene parliamentarians were elected to the European Parliament at elections on 13 June 2004. In 2004 Slovenia also joined NATO. Slovenia subsequently succeeded in meeting the Maastricht criteria and joined the Eurozone (the first transition country to do so) on 1 January 2007. It was the first post-Communist country to hold the Presidency of the Council of the European Union, for the first six months of 2008. On 21 July 2010, it became a member of the OECD.