Subject Region
United States
40
Japan
35
Europe
18
Asia
13
East Asia
13
Germany
10
China
9
European Union countries
8
France
8
Developing countries
7
Southeast Asia
7
European Economic Community countries
5
Korea (South)
5
Germany (West)
4
Great Britain
4
Mexico
4
Africa, Southern
3
Africa, Sub-Saharan
3
Canada
3
Europe, Central
3
Europe, Eastern
3
Mexican-American Border Region
3
Thailand
3
Denmark
2
Europe, Western
2
Finland
2
Former Soviet republics
2
Hong Kong (China)
2
Ireland
2
Israel
2
Middle East
2
North America
2
Russia (Federation)
2
Saudi Arabia
2
Scandinavia
2
Singapore
2
Soviet Union
2
Sweden
2
Syria
2
Taiwan
2
Yemen (Republic)
2
Arab countries
1
Europe, Southern
1
Italy
1
Latin America
1
Mediterranean Region
1
Philippines
1
South Africa
1