According to Simpsons Wiki, In 25 Seasons, she's appeared in 56 episodes
None, the Simpsons as a series didn't air on T.V. until 1989
21
25
234 episodes aired during that decade.
22
21 eps .
At the end of 2012, 516 episodes had aired.
There have been references to SpongeBob in The Simpsons episodes and the character appears in several Simpsons episodes. SpongeBob is also referenced in a couple of Simpsons comics.There are also a couple of references to The Simpsons in SpongeBob SquarePants episodes.
There are zero unaired episodes of The Simpsons. I suppose technically the newest season 29, which debuted on October 01st 2017, is filled with 'unaired' episodes but naturally there is a distinct difference in episodes that were supposed to air & didn't and completed episodes that haven't been scheduled to air.
429 at the start of 2009449 by the end of 2009
24 Minutes