Here's a map of the world plotting out Marvel characters and there's no surprise which state is best at pumping them out.
Basically, if you want to be a successful superhero in the Marvel universe, you should probably find some way to be born in New York, or at the very least, be from some big city in the United States. Though there are exceptions—Wolverine is Canadian, after all—it seems like the rest of the world is lacking in superheroes.
But the super villains... it seems that all the baddest bad guys come mostly from the rest of the world (I'm looking at you, Dr. Doom, Magneto, Apocalypse, Abomination, Arcade...)
Hooray for comic book bias.