Final answer:
The United States had a favorable balance of trade in 1971, selling more to other countries than it bought from them.
Step-by-step explanation:
The balance of trade refers to the relationship between a country's inflow and outflow of goods. In the case of the United States, by the year 1971, it had a favorable balance of trade, meaning it was selling more to other countries than it bought from them. This is also known as a trade surplus.
The trade surplus or favorable balance of trade can be seen in the graphs from the 1960s into the 1970s, as positive numbers are shown. However, in the 1980s, the United States started experiencing a trade deficit, which means it was buying more goods and services from other countries than it was selling to them. This trade deficit has persisted and even increased over the years.