Region
United States
20
Soviet Union
15
United States --
8
Soviet Union --
4
Europe
3
Europe --
2
Former Soviet Republics
2
India
2
Iran
2
Iraq
2
Korea (North)
2
Arctic region
1
Canada
1
Canada --
1
East Asia
1
Former Soviet Rebuplics
1
Former Soviet republics
1
Germany (West)
1
India --
1
Iraq --
1
Korea (North) --
1
Korea (South)
1
Korea (South) --
1
Pakistan
1
Scandinavia --
1
South Asia
1