Windows Phone: Windows Phone 8.1 now represents 65% of Windows Phone downloads while downloads from Windows Phone devices running 7.x account for less than 5%.
US is still the market with most app download but China, India, France, United Kingdom, Brazil, Mexico and Russia are significant too.
The market with most downloads is United States, though the distribution of downloads shows there are many markets generating a significant number of downloads, such as China, India, France, United Kingdom, Brazil, Mexico and Russia. That doesn’t mean, however, that you shouldn’t consider other markets as well. Your apps may have specific characteristics more suitable to these markets.
Last but not the least carrier billing support has been extended to more markets.
Additions this December include Verizon Wireless in the U.S., as well as mobile carriers in new markets such as India, Vietnam, Brazil, and China, all of which are in the top Windows Phone markets. With these additions, the Store now has established connections with 46% of all subscribers worldwide, more than any other major smartphone platform supports today (Source: Ovum World Cellular Information Service).