I'm going on the lower end with 32.5 - 34.9 million, because...
Bonus: It seems insane to think they won't release a new Mario Kart for possibly 10+ years, depending on when Switch's successor launches. People need to remember it's already been 6 years since it released on Wii U, and outside of fixing battle mode which was practically an unfinished project, they haven't added any new maps since the last DLC pack for Wii U.
There's enough time to launch MK9 for Switch in 2021/2022, have that fuel sales until the Switch's successor in 2024/2025, and still have the next Mario Kart ready for that system possibly year two or three. Rather than the stale approach of launching a system with a new Mario Kart (having to hold it back for years and avoiding all those potential sales on Switch, plus the extra boost for Switch), they'll actually try something like maybe a reboot of F-Zero in year one, with a new Mario Kart a couple years later.
If MK8 was going the distance, I have to believe we would've gotten some new DLC by now.
