How Fast Are Black Holes Growing?

A new study shows that black holes are growing much more quickly than the galaxies they're in. The theory could be explained by the idea that the black holes are basically eating the galaxies. We actually do expect galaxies to grow because 40 to 50% of all protons in the universe are not in galaxies yet. And so maybe it could have just be that the black hole are eating up their own galaxies and getting bigger that way.