1985
1988
2009
SMB 2 wasn't a Mario game. Lost Levels was SMB-b, expansion pack. Super Mario World was SMB 3b, a Yoshi expansion pack.
Rules
Spinoffs including 3D Mario don't count, we all know the N64 should have had 4 player Mario instead of 3D gimmickry.
NSMBWiib will not count as a new Mario game just as World and Lost levels doesn't count. NSMB Wii with 3D gimmickry will not count as a new Mario game.
Gimped handheld versions that should never have been made or should have used a different IP don't count.
So when will the new REAL Mario game release?
Nov 2016 - NES outsells PS1 (JP)
Don't Play Stationary 4 ever. Switch!