PS4 was up YOY by 23% in USA the second year, XB1 was up by 13%, and it god 2 massive pricedrops and a lot of insane bundles.
Even Wii U was up by like 25% or so the second year, the only recent system i rememb being down compated to the first year is 3DS, which had a massive pricedrop and a weak lineup in 2012, and PSVita, which, well... Was just left to die.
PS4 sales:
2014 - 4.68m
2015 - 5.73m
oh wel,l i guess i was wrong. I remember when there another year ps4 sold 4 million. Can you post all other years NPD for ps4 LTD.