When did Kermit first sing "Not Easy Being Green?"

[Fozzie54]

I remember Rainbow Connection in the Muppet Movie, but when was the first time Kermit sang "It's Not Easy Being Green?" Clearly I haven't been watching enough Muppet stuff lately and am embarrassed to say I don't know. What's the best place to look something like that up?

Thanks!
Fozzie54

 

[D'Snowth]

I think it was 1969 for Sesame Street.