You are all wrong ;)
1987 is the corrrect answer. (if we play by american release dates)
How about these megaton releases:
Mega Man
Castlevania
The Legend of Zelda
Punch Out
Metroid
Kid Icarus
In europe I would go with 1991 which has even more megaton releases
Little Nemo
Chip n Dale
Turtles II
SMB3
Ninja Gaiden
Journey to Silius
Blaster Master
Over Horizon
F-Zero
Super Mario World
Super R-Type
UN Squadron
Actraiser
Supercastlevania IV
Final Fight
*drops mic, leaves room*