sell-through will be a little over 48m by end of year. Possibly a bit more.
If we're going by current VGC numbers as the starting point.
9m = 17.8m year total.
10m = 18.8m year total. (lines up perfectly with my previous prediction in sig, so this is what I'm voting for.)
11m = 19.8m year total.
13m = 21.8m year total.
10/11 Million are the most reasonable answers I think, (48.3m/49.3m by years end)
13m is too high, 9m is a little too low.
Predictions (Made July 2019)
LTD: PS4 - 130m, Switch - 110m, XBO - 52m 2019 : PS4 - 15m, Switch - 18.8m, XBO - 4.8m 2020: Switch - 22m (Peak Year)