Some sources even say 170 mill for SD but I think that should be worldwide, 130mill japan only.
Right now KnY should have around 90m physical+ let's say 20% digital, let's go with 110mill, so yeah it's definetly gonna beat Slam Dunk, Naruto is 140m, but Kochikame's sales are 158'770,000 just a bit below DB's 160'000,000 (Though those supposed sales are from April '14, I think DB has since gotten a tankobon reprint with a new spine and a combini edition so it might have sold more, maybe it's at 170mill...)
The scary thing is that
right now KnY is Jump's biggest domestic seller per volume, because I believe the reported 170mill of Slam Dunk are worldwide sales (I even asked EasyLove, the guy that makes
JUMP's top seller videos and he/she said that it was probably a mistake that SD had sold 170mill in Japan, those were numbers mentioned in a TV quiz show in Japan in 2018 but were probably worldwide sales.
Anyway right now KnY only with its confirmed physical sales of 90mill with 22 volume averages 4'090,909 sales per volume. That's without digital sales, and we already know that some volumes have sold upwards of 4'300,000 (Again.. this is just physical sales numbers).
And don't get me wrong its total sales are a monstrosity, but the real monstrous thing is that it only has 22 volumes (23 soon) and it's likely reaching the numbers made by a 72 volumes manga powerhouse Naruto and 200 volume classic Kochikame with only a fraction of their volumes and.. it literally did that in a span of a year.
My one final hope is KnY doesn't get 4.05 million first print, I don't want that record taken from One Piece