Region
United States
40
Soviet Union
24
Europe
20
Great Britain
12
China
8
Germany
6
Japan
6
Developing countries
4
Europe, Eastern
4
France
3
Russia
3
Turkey
3
Africa
2
Italy
2
Manchuria (China)
2
Africa, Southern
1
Asia
1
Athens (Greece)
1
BRIC countries
1
Caribbean Area
1
Europe, Central
1
Germany (East)
1
Germany (West)
1
Islamic countries
1
Korea
1
Middle East
1
Pacific Ocean
1
Russia (Federation)
1
Southeast Asia
1
Spain
1