Region
United States
636
Alaska
12
China
11
Developing countries
9
European Union countries
9
Colorado
6
Europe
3
Great Britain
3
Pennsylvania
3
Africa
2
Africa, Sub-Saharan
2
Cayman Islands
2
Foreign countries
2
Germany
2
Illinois
2
Iran
2
Montana
2
New York (State)
2
Ohio
2
Washington (D.C.)
2
Wisconsin
2
Africa South of the Sahara
1
Anchorage
1
Asia
1
Burma
1
California
1
Chesapeake Bay (Md. and Va.)
1
Conowingo Dam (Md.)
1
England
1
Ghana
1
Hinsdale
1
Iraq
1
Lancaster County
1
Maryland
1
Nevada
1
OECD countries
1
Oak Park
1
Rochester Metropolitan Area
1
Soviet Union
1
Susquehanna River
1
Susquehanna River Watershed
1
Taiwan
1
Texas
1
Wales
1
Washington Metropolitan Area
1
West Virginia
1
Yellowstone County
1
Yellowstone River
1
York County
1