Mark Perry of the conservative American Enterprise Institute argued that the report undercut the woeful conventional wisdom about a shrinking middle class, because the middle class is actually moving up the income ladder, not down. Matthew Yglesias of Vox resorted to Dickens’s sunnier side: “We are currently living through the best of times.”

But the question remains: best for whom? Poorer households did get a bigger raise, proportionally, than the rich did last year. But that looks like a bug, not an enduring feature of the American economy. The data does little to suggest that the American economy has managed to overcome its perhaps most debilitating weakness: inequality.

Despite last year’s gains, the bottom 60 percent of households took a smaller share of the income pie than four decades ago. The bottom 20 percent took in only 3.4 percent of all income — compared with 5.6 percent in the mid-1970s. The richest 5 percent of Americans, by contrast, have done much better for themselves — taking in about 22 percent of the nation’s income, 6 percentage points more than they did in 1975.

America’s inequities can be sliced in different ways. For instance, champions of the nuclear family will underscore the report’s finding that married couples in which both spouses work saw incomes rise by nearly $4,000 last year — to almost $104,000 at the median, the highest ever.

The problem is that the two-earner family is not as iconic as it once was, falling as a share of all families over the past two decades. The families that have been growing are those headed by a single woman. Last year their incomes rose sharply — to $34,126. Sure, that was a big jump on 2014. But they were still making less than they were 15 years before.