United States 545
Europe 55
Latin America 37
Soviet Union 30
Developing countries 29
Great Britain 29
Japan 28
China 27
Africa 24
Germany 18
Southern States 18
France 17
Middle East 15
Asia 14
England 14
Canada 13
East Asia 12
Mexico 12
Earth (Planet) 11
North America 11
Rome 11
Spain 10
India 9
New Mexico 9
Pacific Area 9
Austria 8
European Economic Community countries 8
Greece 8
Italy 8
Foreign countries 7
Southeast Asia 7
America 6
Arizona 6
Caribbean Area 6
Germany (West) 6
Michigan 6
Netherlands 6
New York (State) 6
Africa, Sub-Saharan 5
Arab countries 5
Central America 5
Europe, Eastern 5
Ireland 5
West (U.S.) 5
Appalachian Region 4
Australia 4
Cuba 4
Ethiopia 4
Israel 4
Michigan Basin (Mich. and Ont.) 4
New England 4
Scotland 4
South Africa 4
South America 4
Africa, Southern 3
Africa, West 3
Antarctica 3
California 3
Egypt 3
Gondwana (Continent) 3
Great Lakes Region (North America) 3
Illinois 3
Iowa 3
Islamic countries 3
Mediterranean Region 3
New York 3
Northern Ireland 3
Persian Gulf Region 3
Poland 3
Québec (Province) 3
Russia (Federation) 3
South Asia 3
Southwest, New 3
Africa, East 2
Andes Region 2
Argentina 2
Byzantine Empire 2
Chile 2
Colorado River Watershed (Colo.-Mexico) 2
Lebanon 2
Macedonia 2
Maryland 2
Massachusetts 2
Mississippi River Valley 2
Montana 2
Moon 2
Nigeria 2
North Atlantic Region 2
Ohio 2
Pella 2
Pennsylvania 2
Southwestern States 2
Sweden 2
Tropics 2
Vietnam 2
Wales 2
Afghanistan 1
Albany 1
Algeria 1
Aphrodisias (Extinct city) 1