Region
United States --
14
Soviet Union --
4
United States
4
Developing countries --
3
Africa --
2
Asia, Southeastern --
2
Europe --
2
Germany (West) --
2
Great Britain --
2
Russia
2
1955-
1
Asia --
1
China --
1
Developing countries
1
France
1
Germany (East) --
1
Great Britain
1
Russia --
1
Soviet Union
1
Sweden
1
United State --
1