Subject Region
United States
29
West (U.S.)
5
China
3
Foreign countries
3
Hong Kong
3
Zimbabwe
3
Arizona
2
Botswana
2
California
2
Chesapeake Bay Watershed
2
Developing countries
2
Ghana
2
Great Britain
2
India
2
Ontario
2
South Africa
2
Africa
1
Australia
1
European Union countries
1
Great Basin
1
Idaho
1
Lesotho
1
Mediterranean Region
1
Owyhee County
1
Owyhee County (Idaho)
1
San Francisco Bay Area
1
Southeast Asia
1