Chronological release order for the first Pokémon games?

[*Laurelindo*]

Thank you.

One more question, by the way:
why exactly did Pikachu end up being the whole series' mascot?
I mean, he seems like a random Pokémon in the bunch to me, and you would expect that Bulbasaur should be the real mascot, since he's no. #1 and appeared as one of the very first monsters in the first games.
Sure, he's cute and adorable and everything, but so are lots of other Pokémons (like Jigglypuff, for instance).