A weighted average of the exchange rates between the domestic currency and the nation's most important trade partners, with weights given by the relative importance of the nation's trade with each of these trade partners. Suppose that 40% of home trade is with country 1 and 60% is with country 2. Home's currency appreciates by 10% against country 1 but depreciates by 30% against country 2. By how much home country's currency appreciates/depreciates?