In the late twentieth century, America underwent its big switch -- the transformation from a broadly middle class, manufacturing-based economy, to a financially polarized, services-based economy. Union rolls plummeted as Wall Streets profits surged, and the demand for factory workers were supplanted by the need for healthcare professionals, teachers, and computer engineers.

This is a narrative that, by now, is probably familiar to you. But it's also abstract.



The two graphs below, adapted from a new working paper by University of Pennsylvania economist Jeremy Greenwood and the Census Bureau's Emin Dinlersoz on the rise and fall of U.S. labor unions, tell the tale more concretely. They track the fastest-declining and fastest-growing occupations between 1983 and 2002. I've organized them by color. Occupations that were less than 20 percent unionized are in BLUE; between 20 and 40 percent unionized are in GREEN; and more than 40 percent unionized are in RED.

In roughly 20 years, entire categories of factory work nearly disappeared. If your job hinged on your aptitude with a shoe machine, it was in danger. Likewise if you worked a lathe every day for a living, or had a spot anywhere else on a classic production line, where dozens of hands handled simple, discreet tasks. (How sociologists ended up on this list, I'm frankly not sure.) These were jobs that, thanks to their heavy levels of unionization, paid a good middle class wage to employees without many skills. And when manufacturing technology improved, they became redundant.