Okay I'm back. I redid Gen 2 as the OP one is slightly wrong. Here is an accurate version. It is strange that people used to think Johto had bad distribution - you can get almost all the mons fairly early on; it's no less balanced than Gen 1 or Gen 3 and beyond.
>>55698946 Pic related is now accurate. Also, whether or not you can get all 3 starters is based on how many games/friends you have to trade with. But that is the same for every single Generation, so this is the best way to display the starters for each Gen.
Gen 3 next.