PSP dying off so quickly hasn't helped things. As a % it dropped a hell of a lot, but in terms of raw numbers it isn't the main contributor to the drop.
3DS being down 50% is the main cause of that, nearly 700k units. Add in the PS3 showing a more reasonable decline and the WiiU failing to gain any traction compared to last year, and the Vita's +100k and even the release of the PS4 is merely a drop in the water.







