Subject Region
United States
386
Great Britain
151
Japan
72
China
59
Pennsylvania
54
Mexico
44
Developing countries
40
England
39
Europe
37
Germany
37
Soviet Union
37
France
35
India
25
Scotland
22
Massachusetts
21
Canada
17
Ireland
16
New York (State)
16
Southern States
16
Latin America
14
Taiwan
14
Brazil
12
East Asia
11
Korea (South)
11
Italy
10
North America
10
Africa
9
Argentina
9
Australia
9
California
9
Ohio
8
Asia
7
European Economic Community countries
7
Netherlands
7
North Carolina
7
Pittsburgh
7
Russia
7
Alabama
6
Germany (West)
6
London
6
New Jersey
6
Ontario
6
Philadelphia
6
South Africa
6
South Carolina
6
Spain
6
Wales
6
Africa, Sub-Saharan
5
Austria
5
Belgium
5
more ...