How come SEGA doesn't count the first time Sonic characters appeared in a piece of media as their anniversary?
>Sonic: Rad Mobile (Oct. 1990, arcade)
>Eggman: Puzzle Construction (May 1991, TeraDrive)
>Vector: Sonic the Hedgehog Story Comic (June 1991, manga)
>Amy: Sonic the Hedgehog in Shogaku Ninensei (April 1992, manga)
>Mighty: Sonic the Hedgehog in Shogaku Ninensei (April 1992, manga)
>Ray: Sonic the Hedgehog in Shogaku Ninensei (April 1992, manga)
>Charmy: Sonic the Hedgehog in Shogaku Ninensei (Sept. 1992, manga)
>Tails: Sonic 2 8-bit (Oct. 1992, Master System)