The country applied in June 1993 for membership in the European Union and became an Associated State of the EU in 1995 , an Acceding Country in 2004 , and a member on January 1 , 2007 . The country applied in June 1993 for membership in the European Union and became an Associated State of the EU in 1995 , an Acceding Country in 2004 , and a member on 1 January 2007 .