A country's trade efficiency is a number which abstractly quantifies how good its trading is. Trade efficiency (abbreviated TE) is used in the computation of trade taxes and trading income, as well as success in getting merchants into centers of trade, and their stickiness once in.
Trade efficiency is determined based on a country's trade technology, domestic policies, religion, and several other factors. The base level of trade efficiency is a function of the country's trade technology level:
Trade Base TE 0 20% 1 30% 2 40% 3 50% 4 55% 5 60% 6 65% 7 70% 8 80% 9 90% 10 100%
Then the following modifiers apply:
- Aristocracy domestic policy setting: +5% to -5%
- Land domestic policy setting: +5% to -5%
- State religion is Reformed: +10%
- State religion is Counterreform Catholic: -10%
- Refineries: +1% for each one
- Trade agreements: -1% for each one
- Each monopoly: +2%
- Each trade embargo: -3%
Trade efficiency cannot be lower than 0%, but it can rise above 100%. When trade efficiency is greater than 100%, a country gets a special bonus of +50% on its chances to create and expand trading posts.