Final answer:
Over the past three decades, the U.S. has shifted from an Industrial economy to a Service economy, with a notable increase in service sector jobs and decline in manufacturing.
Step-by-step explanation:
The United States has shifted from an Industrial economy to a Service economy over the past three decades. Following the Industrial Revolution, the U.S. economy was dominantly industrial, with a workforce heavily engaged in manufacturing jobs. However, as time progressed, particularly in the latter part of the 20th century, there has been a marked increase in service jobs. This transition is further illustrated by the reduction of manufacturing jobs, which peaked in the late 1970s and have since declined by more than a third. Today, the service sector employs a large portion of the American workforce, dominating the economic landscape and marking a significant shift in the country's economic structure.