| Country | 1987-1992 | 1993-1996 | 1997-2000 | 2001-2007 | 2008-… |
| Armenia | x | ||||
| Austria | x | x | x | x | x |
| Bosnia & Herzegovina | x | x | x | ||
| Bulgaria | x | x | x | x | x |
| Croatia | x | x | x | x | |
| Czech Republic | x | x | x | x | x |
| Georgia | x | x | x | x | |
| Germany | x | ||||
| Greece | x | x | x | ||
| Hungary | x | x | x | x | x |
| Italy | x | x | |||
| Lithuania | x | x | x | ||
| Poland | x | x | x | x | x |
| Romania | x | x | x | x | x |
| Russian Federation | x | x | x | x | |
| Serbia | x | ||||
| Slovakia | x | x | x | x | |
| Slovenia | x | x | x | x | |
| Turkey | x | x | x | x | x |
| Yugoslavia | x | ||||
| TOTAL COUNTRIES | 11 | 12 | 15 | 16 | 16 |
