Xbox One was number one back in November, and it looks like they did it again for December. We'll be getting sales data for the US from the NPD later today, but Microsoft revealed that they came out number one in console sales in the US once again in a press release today.
The Xbox One is performing even better than the Xbox 360 during the same period, as Microsoft wrote in a press release, "Weekly average sales during these months outpaced Xbox 360 by 50 percent at the same point in its lifecycle." However, the Xbox 360 hit its own milestone by becoming "the best-selling seventh generation console of all time in the U.S."
In addition to having the number one console, Microsoft also trumpeted their success on the software front, writing, "Xbox One sold more games throughout November and December in the U.S. than any other current-generation platform."