I know these things are classics but, exactly how long have they been in production? I know I've been wearing them (different pairs) for at least 5 years. The Adidas website has no real info.

They Come in 4 styles.

Samba classic : made from oxhide
Samba classic k : same as classic, but kangaroo leather uppers.
Samba nubuck : nubuck uppers, slightly smaller tongue.
Samba Milenium : Has very little in common with the trusty Classics. A complete redesign, complete with high-tech gimicky soles. A perfect example of spaceship shoes.