Região
Developing countries
Asia
15
Africa
9
Soviet Union
7
Communist countries
6
Europe, Eastern
5
United States
5
Arab countries
2
Africa, North
1
Asia, Southeastern
1
China
1
Europe
1
European Economic Community countries
1
India
1
Japan
1
Middle East
1
Mongolia
1
Philippines
1
Russia (Federation)
1
South Asia
1
Thailand
1
Vietnam
1