The shift in the United States, from being an agricultural based economy to being a manufacturing based one occurred in the first half of the 18th century, with the industrial revolution. During this period, there were numerous improvements to the production processes in diverse industries, such as in iron production processes, and particularly in the textile sector.
Improvements included the replacement of hand production stages for machines, an increase in the use of steam power, and the factory system, which centralized all stages in the production process under one roof.
A couple of centuries later, towards the end of the 20th century and the beginning of the current 21st, came the shift from a manufacturing based economy to a service based one. This change was influenced by the effect of globalization, which saw numerous manufacturing process of American companies move overseas to countries where production costs were significantly lower. On the other hand, the rise of the technology industry saw an impressive growth in US companies in this sector. These companies now offer their services through the software and applications they offer.