Region
Afghanistan
7
Africa
2
Africa, Southern
1
Arab countries
2
Argentina
1
Asia, Central
2
Azerbaijan
1
Canal Zone
1
Caribbean Area
1
Central America
1
China
1
Colombia
4
Europe
1
Former Soviet republics
1
Great Britain
1
Indian Ocean Region
1
Indo-Pacific Region
1
Iran
1
Iraq
3
Israel
2
Kazakhstan
1
Latin America
3
Middle East
1
Nigeria
3
Panama
2
Panama Canal (Panama)
2
Russia (Federation)
2
Soviet Union
1
Sri Lanka
1
Syria
5
Turkey
1
Ukraine
3
United States
36
Yemen (Republic)
1
Yemen, North
1
Yemen, South
1
Zimbabwe
1