Oblast
United States
21
European Union countries
15
Europe
10
China
4
Africa
3
Europe, Eastern
3
Russia (Federation)
3
Soviet Union
3
Canada
2
Developing countries
2
Germany
2
Great Britain
2
Israel
2
Turkey
2
Arab countries
1
Asia
1
Czechoslovakia
1
Europe, Central
1
Finland
1
France
1
Germany (West)
1
Japan
1
Korea
1
Korea (North)
1
Korea (South)
1
Latin America
1
Mediterranean Region
1
Middle East
1
Poland
1
Southeast Asia
1
Switzerland
1
Ukraine
1