1.8m in two months in the US alone. Switch basically got an extra holiday season this year. Crazy.
I hope this is close enough for you. I included the "appropriate" reply in the link.
You even said 50m! That was bold. I agree, the way things are playing out i think the game will finish closer to 50m than 40m. This would make it the best selling game on a single console in history and no i don't count the free pack in that was wii sports.