There don't seem to be more than about 23000 nukes in the world today.
Source : wiki and some other sites
But i might know why Vegas got the love : "States with the largest number of nuclear weapons (in 1999): New Mexico (2,450), Georgia (2,000), Washington (1,685), NEVADA (1,350), and North Dakota (1,140)"
Source : www(dot)brookings(dot)edu/projects/archive/nucweapons/50(dot)aspx
Otherwise it doesn't make sense , 80 nukes on just one US state seems a waste unless the Chinese prime minister lost a poker tournament or something ...
Also , despite the NPCs constantly bitching about how hot it is , and a nuclear winter would be great , it's just as possible to have a nuclear summer.

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