First appeared in the Spider-Man and His Amazing Friends episode "The Triumph of the Green Goblin" on September 12, 1981 and made her comic debut in Spider-Man and His Amazing Friends a few months later.
This is going off the debut of comic book characters. In the cases of characters who were introduced in other media originally and added to the comics canon later along (ex: Harley Quinn) it'll go by actual debut year.
