mtiks is a mobile analystics company who monitors app usage as well as piracy on various platforms, including Windows Phone 7. They just released some numbers for February that they've collected and while it is a limited selection, the trend seems to be clear: HTC and the United States dominate Windows Phone 7 app usage.
That's probably not too surprising--the U.S. is the home base for Microsoft and AT&T and T-Mobile did push out five devices in 2010 supporting the OS. On the other hand, the U.S. also launched WP7 a month later and is missing on two carriers (CDMA). Regardless of the reason, 57.3% of app stats by country puts the United States at number one, which is a commanding lead over second place Germany (18.5%) and 7.5% in the UK. In addition, the numbers for the States will probably go up once all four carriers begin to offer devices, with Sprint and Verizon joining by the end of March.
In terms of device usage, it's probably of little surprise that HTC is winning there with 35% of apps being run on an HD7 (either branded or unlocked). But creeping up on HTC's tail is of course Samsung, who's Focus takes a nice 24% of the pie--an impressive feat when you consider the more limited run of the Focus. HTC may have the reach and multiple devices (56% total) but Samsung is clearly catching up having 32% share with only two phones. Also of interest, is LG, who only has 12% of all the app-using devices.