Region
United States
6
United States --
3
Europe, Eastern --
2
Germany (West)
2
Germany (West) --
2
Great Britain --
2
Romania --
2
Soviet Union
2
Soviet Union --
2
Afghanistan
1
Afghanistan --
1
Asia, Central
1
Asia, Central --
1
Canada --
1
Central Asia
1
Commonwealth countries
1
Cyprus --
1
Developing countries
1
Developing countries --
1
Europe
1
Europe --
1
Europe, Eastern
1
Foreign countries
1
Great Britain
1
Greece
1
Greece --
1
Japan
1
Japan --
1
Mexico
1
Mexico --
1
Nigeria --
1
Pakistan
1
Pakistan --
1
Philippines --
1
Romania
1
Soviet Central Asia
1
State, The
1
Turkey
1
Turkey --
1