What year did each Muppeteer join the group?

[Fighbird]

Kevin Clash - 1984/5/6?

How about David Rudman, Joey Mazzarino, Marty Robinson, Stephanie D'Abruzzo, Fran Brill, Noel MacNeil, Bill Barretta, Brian Henson, Eric Jacobson?

I've heard 1984 for Kevin Clash as well, and 1986 is definitely too late because he was involved in Labyrinth that premiered that year (a movie that took at least a few years to do).

By the same reasoning, I think Bill Barretta joined in 1990, with Dinosaurs premiering in early 1991.

Brian Henson did some freelance work on The Great Muppet Caper, but I think his first major Muppet production was Labyrinth (again, ca. 1985 if not earlier).

I think Eric Jacobsen once said he started on Sesame Street in 1994.

But what are the exact years we are looking for? People joining the company, people performing for the company, or people performing main Muppet Show/SS characters?