Souvenir Cup History

Hey everyone,
I just wanted to ask about the refillable cedar point souvenir cups. How long have they done this? Does anyone have any older ones, that would be willing to post pictures? The oldest one that I can remember is the 2002 Wicked Twister one, but other than that, I can't remember.

Thanks.

P.S here's some on coaster image.com

http://www.coasterimage.com/features/souvenircups/index.htm

They have had souvenir cups dating back to when I worked at CP between 1981 and 1983.