In Europa Universalis II, trade is one of the more important parts of managing your economy. There are three different kinds of income associated with trade. In-game, two of them are grouped under your monthly tax income, and the other under your monthly trade income. Tolls are the sum of trade taxes from all provinces and depends on province population and your trade efficiency. They are lumped with other taxes. Trade revenue depends on the number of merchants you have in center of trades. The annual figure is as follows: number of merchants * percentage of CoT value * trade efficiency