Subject Region
United States
424
Great Britain
22
Europe
18
Australia
17
Developing countries
17
India
17
New York (State)
15
California
14
Canada
14
New York
13
Pennsylvania
9
Ukraine
9
Africa
8
China
8
Iraq
8
Mexico
8
Afghanistan
7
England
7
Mexico, Gulf of
6
South Africa
6
West (U.S.)
6
Botswana
5
Japan
5
Ontario
5
Pakistan
5
Africa, Sub-Saharan
4
Alaska
4
Europe, Eastern
4
Latin America
4
Marshall Islands
4
Mediterranean Region
4
Nigeria
4
North Carolina
4
Vietnam
4
West Virginia
4
World Trade Center Site (New York, N.Y.)
4
Alabama
3
Anniston
3
Belarus
3
Caribbean Area
3
Colombia
3
Connecticut
3
Huancavelica
3
Middle East
3
Navajo Indian Reservation
3
Nevada
3
Nicaragua
3
Outer space
3
Peru
3
Rongelap Atoll
3
more ...