Region
United States
23
Soviet Union
11
Great Britain
6
Developing countries
4
East Asia
2
Europe
2
France
2
South Africa
2
Southeast Asia
2
Berkeley
1
California
1
China
1
England
1
Europe, Western
1
Geneva
1
Germany
1
Germany (East)
1
Germany (West)
1
London
1
Russia
1
Russia (Federation)
1
Switzerland
1