Region
United States --
3
China --
2
Developing countries
2
Developing countries --
2
United States
2
Asia, Southeastern --
1
Australia
1
Australia --
1
Caribbean Area
1
Caribbean Area --
1
Central America
1
Central America --
1
Great Britain --
1
Hampton Roads
1
Japan --
1
Malaysia
1
Soviet Union --
1
Virginia --
1