| year joined | Country | % Correct |
|---|---|---|
| 1958 | Belgium | 100%
|
| 1973 | Denmark | 100%
|
| 1995 | Finland | 100%
|
| 1958 | Germany | 100%
|
| 1981 | Greece | 100%
|
| 1973 | Ireland | 100%
|
| 1958 | Italy | 100%
|
| 1958 | Luxembourg | 100%
|
| 1958 | Netherlands | 100%
|
| 2004 | Poland | 100%
|
| 1986 | Portugal | 100%
|
| 2004 | Slovakia | 100%
|
| 2004 | Slovenia | 100%
|
| 1986 | Spain | 100%
|
| 1995 | Sweden | 100%
|
| 2007 | Bulgaria | 96%
|
| 2013 | Croatia | 96%
|
| 2004 | Czech Republic | 96%
|
| 2004 | Estonia | 96%
|
| 1958 | France | 96%
|
| 2004 | Hungary | 96%
|
| 2004 | Latvia | 96%
|
| 2004 | Lithuania | 96%
|
| 2007 | Romania | 96%
|
| 1973 (2020) | United Kingdom | 96%
|
| 1995 | Austria | 91%
|
| 2004 | Malta | 91%
|
| 2004 | Cyprus | 87%
|