According to Tyzhang:

FLOOR(FLOOR(FLOOR(FLOOR(FLOOR(FLOOR(FLOOR(population/100+sites_events)(1+admin/200))(1+order_mod))(1+growth_mod))(1+prod_mod))(1+heat_mod))/(1+0.02unrest))

I feel like more research might be needed to get to the bottom of things like fort admin bonus, riches from beneath, nation income penalty... - Loggy

--- Is this for income? - mergele