Region
Europe
Europe --
United States
3
United States --
3
Asia
2
Asia --
2
Soviet Union
2
Soviet Union --
2
Asia, Southeastern
1
Asia, Southeastern --
1
Austria
1
Austria --
1
Canada
1
Canada --
1
Developing countries
1
Developing countries --
1
East Asia --
1
Germany
1
Germany --
1
Great Britain
1
Great Britain --
1
Japan
1
Japan --
1
North America
1
North America --
1
North Atlantic Treaty Organization --
1