Economic integration with the goal to reduce customs duties between each other within a group that made an agreement to minimum or normal tax rate is 0%, and the country itself.
Economic integration with the aim to reduce tariffs within group agreement to a minimum or to 0% and the tax rate is normal with countries outside the EU.
Economic integration with the goal of reducing tariffs within the group that made a deal ให้เหลือ minimal or 0% and use normal tax rate with countries outside the group.