Question on Fireflies

[elie]

Hi all!
As I have already written about a hundred times on this forum I absolutely love Fireflies. It is one of my favorite FM songs and I love Stevie's voice when she sings it.
My question is: to my recollection, this song can be found only on Live 1980, right? Does anyone know why? I know the story behind the lyrics, but I don't know when it was written and why it was never included in any studio album.
Thanx!!