Ok people, there are tons of us. Almost 7-billion of us! I don't think it's unreasonable to assume that 1 out of every 100,000 people is actually a "superhero" – using a secret identity to fight crime in the spare time. That works out to ~70,000 (seventy-thousand) superheroes! Even if you assume that only 1 out of every 1 million people is a superhero, you're still left with about 7 thousand superheroes.
Are these people doing such an awesome job that we are truly completely unaware of their existence?
If you're a superhero, I would suggest contacting me. We'll need your talents and abilities when it comes time to fight the zombies!