AMD revealed that its Vega GPU outsold the previous generation by more than tenfold. Queried about more details, AMD revealed it compared sales of the Vega 10 GPU versus the Fiji chip, which was used for the Radeon R9 Fury X, R9 Nano, etc.
Basically, it looks like cryptocurrency miners really drove sales of the Vega GPU. Not a lot of supply hit the retail channel, so now we know where it went and that it was indeed a bigger commercial success than its predecessor.