Even if only 4/5 game's of Zelda have sold more than this number's, i think that Majora 3D can break 5,000,000.
Imo, it will outsell Ocarina of Time 3D that will break 4,000,000 soon.
I also know that many will disagree with me, but that is my prediction.
---------------------------------------------------------------------------------
12 March 2015
1,100,000 (3,900,000 to go)
8 May 2015
2,030,000 (2,970,000 to go)