Region
Developing countries
20
China
13
United States
8
Europe, Eastern
6
Latin America
5
Europe
4
Former Soviet republics
4
Great Britain
4
Russia (Federation)
4
European Economic Community countries
3
Africa
2
Asia
2
European Union countries
2
Nigeria
2
Australia
1
Canada
1
Caribbean Area
1
Commonwealth of Nations
1
Communist countries
1
Czechoslovakia
1
Developingcountries
1
East Asia
1
Japan
1
Nepal
1
Netherlands
1
Pacific Area
1
Russia
1
Ukraine
1
Zambia
1