When did sonic first come out

In 1991.Sonic and enemys were the only people.No tails till 1992.
Ah, remember 1991 it was the year sonic was "born". it was June 23 at 12:00am the first sonic game came out millions of kids bought, played, and finished this game most 12 year olds at the time said "look at that a blue fast hedgehog what will they think of next? he's way better than that fat plummer guy" NN96