Alphabetical OrderAustria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, The Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, and the United Kingdom.
Dates of Joining:1957: Belgium, France, West Germany, Italy, Luxembourg, Netherlands
1973: Denmark, Ireland, United Kingdom
1986: Portugal, Spain
1995: Austria, Finland and Sweden
2004: Czech Republic, Cyprus, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovak Republic, Slovenia.
2007: Bulgaria, Romania