It’s a tough time to be a bank teller, production worker, or other so-called “middle-skilled” professional.

For at least a few decades, employment in those positions – which have historically offered workers without a college degree a berth in the middle class – has been falling sharply. About 25% of the employed workforce in 1985 held middle-skilled jobs; now just above 15% hold those positions, according to a new paper from the Federal Reserve.

Using data from the Department of Labor, Fed economist Chris Smith examined what happened as people moved from one kind of occupation to another, and especially what became of workers in what he calls “middle-type” jobs after they were laid off, fired, or switched careers.

Generally, this hollowing out of the middle of the labor market has hurt younger workers and those without college degrees, many of whom wound up in lower-paying occupations—from bookkeeper to retail clerk, for example