The popular vote was introduced to the European integration process in 1972, when France held the first referendum on enlargement of the (then) European Communities. In total, 54 referendums relating to European integration have now been held in Europe. As Table 1 illustrates, 23 of 28 EU Member States, as well as three non-EU members (Norway, Switzerland, and Liechtenstein), have held at least one referendum on EU matters. Given its tradition of direct democracy, Switzerland alone accounts for eight EU referendums to date, whereas no EU referendum has yet taken place in Germany, Belgium, Portugal, Cyprus and Bulgaria. The bulk of EU referendums (24 of 54) concern membership referendums, with seven of those having taken place in Norway, Switzerland and Liechtenstein.