I did the same thing when I was setting up for my EQDB project. Although I only needed mag 4+ for that, I had previously done all quakes, and at varying resolutions - 1 degree, 2 degree, etc...still have the result images somewhere...

I'm a bit better programmer now and I could redo it and end up with a nice graphical output.

Or are you just looking for a 2d array database with quake counts? Which catalog? (I need to update my catalogs)

Brian