THIRD AGE - CORRUPTION.

I know this is a tired old subject elswhere, but I cant find any real answers:-

I am playing as Dwarves.
I have all the Northern territories from East to West.
My average income, gold per turn, is around 21k.
My wages & army upkeep comes in around 7k p/t.
Corruption is around 6.5k p/t.

I know all the stuff about moving the capital, building government buildings, removing generals with bad traits etc.
But after tinkering with all these variables I am still at 30%+ corruption.

I have many underdeveloped settlements, maybe this will improve with progress?
But I am thinking perhaps corruption settings are high for every faction? is it set high intentionally?
Or maybe Dwarves are greedier than other factions? they do have a reputation.