Well the last time Microsoft updated numbers, they mentioned 4 million shipped to retailers and it was discovered about 3.2 million of those were actually sold to customers. So if they've shipped 5 million worldwide, I think it's reasonable to believe that they've sold somewhere around 4.2 million consoles, making the lead for Sony around 7 million to 4.2 million, which is a pretty significant gap for 6 months into a console generation.

Microsoft is holding their ground in America, but getting destroyed everywhere else. Price cut of $100 or worldwide equivalent and compelling exclusive titles is the only thing that's going to save them, IMO. You can't keep selling a weaker console at a $100 premium, especially when your competitor has been selling like crazy. Price needs to come down ASAP.

EDIT: Absolutely should NOT be taken as evidence, but VG Chartz has the Xbox One listed at 4.2 million and the PS4 at 6.9 million as of April 5th.