How can I find out statistics on the App Store?

I am writing an article and need to find out how many art related applications are in the App Store.

I see articles where people quote statistics on the number of applications for specific things so I know there must be a way to find out but all my snooping has not gotten me any results. I know new apps are arriving at a rate of about 600 a day and that a figure would be ballpark in that regards.

Can anyone help me out here?