Region
United States --
12
United States
10
Soviet Union
7
Soviet Union --
7
Developing countries --
5
Developing countries
3
Great Britain
3
Great Britain --
3
Asia, Southeastern
2
East Asia --
2
France
2
France --
2
Germany --
2
Korea (North) --
2
Africa
1
Africa --
1
Asia, Southeastern --
1
Europe
1
Europe --
1
Germany
1
Germany (West)
1
Japan --
1
Korea (North)
1
Korea (South) --
1
Southeast Asia --
1