Hello Archon. Unfortunately, there is no such official chart, as Plarium doesn't reveal such information, so the game will be more interesting if we don't know what is next.😉 The game is designed to be an endless journey to unknown waters.🤗 I had a chart from a player of another Plarium game, but  as a Sparta  player informed me, it is a bit different than what requirements Sparta's capital needs. Maybe if you post your question to the Our FB  community page, someone might help you, unofficially of course. Here is the link to our FB Plarium Community https://www.facebook.com/groups/465443953557137