The median U.S. worker is enjoying their highest wage growth since 2009, according to the Federal Reserve Bank of Atlanta's wage growth tracker.

This metric showed that the median employee saw pay rise 3.4 percent year-over-year as of April, setting a new record for this expansion.

Bespoke Investment Group argues that the Atlanta Fed wage growth tracker "is probably a better snapshot of wage growth than average hourly earnings," which is published by the Bureau of Labor Statistics in the non-farm payrolls report.

One key difference between the Atlanta Fed's measure and the commonly-reported BLS metric is that the latter is plagued by composition effects, according to the analysts.

That is to say, the BLS print would show that average hourly earnings declined in the event that a baby boomer retired and was replaced by a millennial working for three-quarters of that pay. The Atlanta Fed, meanwhile, tracks how wage pressures for the same individuals evolve over time, thereby removing this cohort effect.

"While the effect described above is usually not a big deal, when labor force flows are very large, there can be an effect," writes Bespoke. "For instance, as a percentage of employment, the number of workers who moved from not in the labor force to employed or from employed to not in the labor force in the last 12 months was in the 98.7th percentile since 1990; in other words, very high."

A look at the sub-indexes shows that the good news doesn't stop there: American income inequality is also being reduced in the process.

The relative performance of wage growth among the median college-educated worker — if we use "college-educated" as a proxy for "higher skilled" (and "higher paid") — underscores that upward wage pressures in the U.S. are particularly acute among lower-skilled workers.

In the history of the Atlanta Fed's series, median wage growth for people with a college education has outstripped that of the index at large in more than 80 percent of occasions.

But over the past 12 observations, annual wage growth for college-educated individuals has failed to exceed wage growth for the median individual on eight instances: