Board Thread:Origin Usernames Corkboard/@comment-108.238.230.230-20131004074131/@comment-17124362-20131005042638

The amount can change because of modifiers. Such as if you have a 4 star rating you will get 4% more income/xp. Also premium decorations can give you higher modifiers. The premium decorations don't have to touch it, they just have to be in your town.