I detected a little discrepancy.
The OP and article say the Xbox One is at 44.02 million units, but the Platform Totals page: (http://www.vgchartz.com/analysis/platform_totals/) has it listed at 44.74 million.
Looking at the numbers on VGC Pro it has Xbox One numbers at 44.02 million. So does the front page. Total on Platform Totals must be off. Though taking a quick look the other platforms are displaying the right number.