That is a global number for all current WP8 devices, which actually doesn't even come close to make a major impact on the global scale, and means very little for the US Market.
Speaking of the US, things will get more interesting the moment Sprint and the rest of the CDMA carriers start selling WP8 devices. It's true AT&T sold the most WP devices in 2012, but also had pretty much all the exclusives, while the OEMs (and perhaps Microsoft) did not make an honest effort to push more devices to CDMA carriers. Hopefully this year would be the year they can also finally enter the heavily CDMA dominant prepaid market, a market completely ignored during WP7 for what ever the reasons are (and I believe it goes beyond coding and encryption).