Region
Soviet Union
30
United States
9
Communist countries
6
Russia
4
Africa, Southern
3
China
3
Cuba
3
Europe
2
Europe, Western
2
Vietnam (Democratic Republic)
2
Africa, Sub-Saharan
1
Berlin (Germany)
1
California
1
Czechoslovakia
1
Developing countries
1
Europe, Eastern
1
Germany
1
Italy
1
Latin America
1
Portland (Or)
1
San Francisco
1
Turkey
1
Vietnam
1