When Bulgaria and Romania joined the EU in 2007, how many member states did the Union then altogether have?

Explanation

The European Union goes back to the 1950s when six states - Benelux, France, Italy and Germany - got together to form the European Coal and Steel Community. Since then, the community has been widened both in terms of scope and members. After the Fall of the Wall, many of the former communist countries were admitted to what was by then a Union. 10 countries joined in 2004 (Estonia, Latvia, Lithuania, Poland, The Czech Republic, Slovakia, Slovenia, Hungary, Malta and Cyprus ) whereas in 2007, Romania and Bulgaria joined.