Over 5mil. It's gonna get more and more content over time and had really good launches in France and Spain. Japan and UK don't really paint the whole picture there.
I expect it to have very good legs and end up ahead of Mario Tennis Aces, which should be over 4mil by now.
Bonus: It's generally a bit annoying, but I tend to buy these games only months after release, so I personally don't mind. It does affect the games reception at launch though, which is a shame.