One that is commonly used to assess trade performance is the growth in the value or volume of exports-imports on average per year or its long-term growth trend.
In export-import activities, tariffs are also referred to as customs, duties, or charges. Tariff is a tax imposed on a commodity traded across territorial borders. Tariffs are generally imposed on imported goods, although some are imposed on exported goods. Tariffs are usually associated with protectionism, economic policies that restrict trade between countries.
There are several substances that are usually covered in bilateral and regional FTAs, including trade in goods, trade in services, investment, labor movement, capacity building, customs procedures, intellectual property rights and so on.