Everyone knows that truck drivers move America, but now it seems that truck drivers also make up America.

According to a recent report by NPR, truck drivers are the single most common occupation in the United States. Their research shows that somewhere between 1978 to 2014, the U.S. went from a nation of farmers and secretaries, to one dominated by truck drivers.

One of the reasons why trucking has grown, when other industries have faltered is due to the fact that a driver is not easily (or at all) replaced by technology. Whereas, many other occupations, such as factory work, have diminished due to machines and automation.

Another reason is that it’s impossible to outsource the jobs to other countries for the cheap labor costs.

Lastly, the demand for consumption has continually risen, and a majority of what’s consumed arrives to it’s destination via truck.

Here’s what the most common jobs per state were in 1978.
truckjobs1

And here’s what it looked like in 2014.
truckjobs2

The demand for driving is also expected to increase by 11% within the next 10 years according to the Bureau of Labor Statistics. And that’s the story of how the U.S. became a nation of truck drivers.