Region
United States --
12
United States
7
Japan --
5
Europe --
4
United states --
4
Developing countries
3
Germany
3
Germany --
3
Foreign countries
2
Great Britain
2
Great Britain --
2
Japan
2
Soviet Union --
2
Africa --
1
Africa, Southern --
1
Caribbean Area --
1
Developing countries --
1
France
1
France --
1
South Asia --
1
Soviet Union
1
Spain --
1
United States - --
1
Yugoslavia
1
Yugoslavia --
1