Microsoft has claimed that as of September 30th 2012, 70 millions units have been sold of the Xbox 360. That compares with the 63.9 million units of the PlayStation 3 sold as of March 31st 2012, and 96.56 million Wii units from June 30th.
To compare the launch times, Xbox 360 was first outed in November 2005, with the Wii and PlayStation 3 following a year later in November 2006. It seems there has been the reported declines in revenues - even according to this data.
The first quarter of the 2013 fiscal year have also had unimpressive shipped units. However, it remains to be a great force in the console world.