After years of progress, the median earnings gap between black and white men has returned to what it was in 1950, according to new research by economists from Duke University and the University of Chicago.

The experience of African-American men is not uniform, though: The earnings gap between black men with a college education and those with less education is at an all-time high, the authors say.

The research appears online this week in the National Bureau of Economic Research working paper series.

The paper looks at earnings for working-age men across a span of 75 years, from 1940 to 2014. The earnings gap between black and white men narrowed during the civil rights era. Then, starting around 1970, the gap between black and white men’s wages started widening once again.

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