Lifespan of a Blood Fin Parrot Fish?

I have had a blood fin parrot fish in my aquarium for literally ten years. How long do they live, out of curiousity? He still seems to be going strong despite all he's been though (for instance I once noticed he had a rock stuck in his mouth and so I got a pair of tweezers and quickly grabbed him and pulled the rock out, then returned him to the tank, and this was several years ago). The only time he ever appears sickly is if I forget to clean the tank for awhile, but after a thorough cleaning he is back to his old self.