The overall GDP number is not very useful when looking for insight into freight conditions in the economy. The U.S. economy is dominated by the service sector, which includes segments like healthcare, education and financial services. These areas make up over half of all of the economic activity in the U.S., but do not play a significant role in freight movements in the economy. As a result, as long as the service sector is healthy, the U.S. economy can continue to grow even if the production and transportation of goods is stalling.