For more than six decades, the European Union has expanded to encompass 28 member countries, and Britain's departure on Friday will mark its first contraction. Here is a timeline: - 1957: Six countries -- Belgium, France, Germany, Italy, Luxembourg and the Netherlands -- sign the Treaty of Rome establishing the European Economic Community (EEC), the precursor to the EU. - 1973: Britain, Denmark and Ireland join the bloc, taking the number of members to nine. - 1981: Greece becomes the 10th member. - 1986: Portugal and Spain join. - 1995: Austria, Finland and Sweden enter what has evolved into the EU, which now has 15 members. Norway rejects accession in a referendum. - 2004: Eight ex-communist Eastern European countries and two Mediterranean nations join up: Cyprus, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia. The bloc swells to 25 members. - 2007: Bulgaria and Romania take the EU to 27 member nations. - 2013: Croatia becomes the 28th. - 2020: Britain becomes the first member state to leave the EU, after a seismic 2016 referendum vote to quit the bloc. bur-jmy/rjm/wai/phz/har