From the AppFigures blog [As of Wednesday, December 9th]:

There are currently 2,624 apps available for download in the Apple TV App Store. That’s quite a number considering the store is just about a month old. With a pretty steady rate of growth so far, we estimate the store will be hitting 5,000 apps in about a month and 10,000 apps in early 2016.

And:

The Games category is the single largest category on the Apple TV App Store with 1,002 apps. This means Games make up roughly 38% of all Apple TV apps.

Lots more data, including some detailed charts. Good stuff.