Water on Earth - Comets or Asteroids?

This is the theory that's most widely embraced. And while perhaps a bit of the original water from Earth may have survived those brutal early formative years, the primary evidence supports an extraterrestrial model. If that's the case, then there's two likely delivery systems, comets and asteroids. So which ratio best matches the water on Earth? Do you think asteroids are comets? I'd say comet asteroids.