PS4 in 13.5 months sold through 18.5 million, switch in 13 months is probably at 15.5 million sold through.
Lol wqit u til November/December when Switch overtakes ps4 again. It will be like this for its whole life time unless somethibg dramatically bad happens. Add on Pokemon and Smash and The Switch could potentially get a big enough boost above ps4 by next year that Switch stays ahead of it forever. It all just depends on how Switch sells later on in its life.