Tariffs have existed since the Middle Ages. Countries have often increased tariffs during difficult times. When the economy is good, tariffs become less common. For example, countries damaged during World War I charged high tariffs after the war to protect their local industries. During the 1920s economies improved, so many countries lowered tariffs. When the Great Depression began in 1929, countries charged high tariffs again.
After World War II many countries agreed that high tariffs hurt international trade. Beginning in 1947 countries made several agreements to limit tariffs. That year 23 countries signed the General Agreement on Tariffs and Trade (GATT). If a member country lowered any of its tariffs, the lower tariff applied to the whole group. The World Trade Organization of more than 100 countries replaced GATT in 1995. In 1994 the North American Free Trade Agreement (NAFTA) removed tariffs between Canada, the United States, and Mexico. Groups of countries in Asia, Europe, and South America have also agreed to end tariffs between group members.
