Apple is likely just quoting third party numbers which have been widely circulated and it's likely they're showing the more favorable NA numbers.
E.g. http://gigaom.com/2013/07/23/the-ipad-accounted-for-84-3-per...
E.g. http://gigaom.com/2013/07/23/the-ipad-accounted-for-84-3-per...
There's probably enough external data to confirm that the iPad owns the real lion's share though.