The sum of exports and imports as a percent of gross domestic product is sometimes used as

Question:

The sum of exports and imports as a percent of gross domestic product is sometimes used as a measure of how open an economy is. In particular, the greater the percent, the more open the economy is considered. Use the following data to compute this measure of the openness of the United States economy in 1960, 1970, 1980, 1990, 2000, and 2009. Discuss what the data show in terms of the €œinternationalization€ of the United States economy since 1960.