As Arindrajit Dube explains,
As a result of legislative inaction, inflation-adjusted minimum wages in the United States have declined in both absolute and relative terms for most of the past four decades. The high-water mark for the minimum wage was 1968, when it stood at $10.60 an hour in today’s dollars, or 55 percent of the median full-time wage. In contrast, the current federal minimum wage is $7.25 an hour, constituting 37 percent of the median full-time wage. In other words, if we want to get the minimum wage back to 55 percent of the median full-time wage, we would need to raise it to $10.78 an hour.