Region
Soviet Union
Soviet Union --
13
Europe, Eastern
3
Europe, Eastern --
3
United States
3
United States --
3
Europe
2
Europe --
2
Asia
1
Asia --
1
Asia, Southeastern
1
Asia, Southeastern --
1
Developing countries
1
Developing countries --
1
East Asia --
1
Former Soviet republics
1
Former Soviet republics --
1
Hungary
1
Hungary --
1
Middle East
1
Middle East --
1
Poland
1
Poland --
1
South Asia
1
South Asia --
1