“The government is still using a black-and-white television,” Chuck Schumer, the Democratic Senate leader, told me. “We gotta catch up, so we get a more accurate picture.” Schumer plans to reintroduce the bill in the coming days, and he said he was hoping that a Republican would co-sponsor it. The expanded version of G.D.P. would include estimates for every decile of the income distribution — 10th percentile, 20th and so on — as well as for the top 1 percent.

If it happens, Heather Boushey, the author of a recent history of the American economy, “Unbound,” says it could be the most significant improvement in economic statistics in decades.

It would also be part of a broader shift. The Federal Reserve created its own distributional accounts recently, to offer more detailed data on wealth. And Australia and the Netherlands have both begun releasing distributional G.D.P. numbers.

The economist who oversaw the first version of G.D.P. in the United States — Simon Kuznets, a future Nobel Prize winner — probably would have been in favor of these developments. Kuznets cautioned that people should not confuse the economy’s total output with economic well-being. “Economic welfare,” he wrote in 1934, “cannot be adequately measured unless the personal distribution of income is known.”

The failure of G.D.P. to include distribution didn’t matter much in the decades after World War II, because economic growth was remarkably inclusive. If anything, the middle class and poor received raises that outpaced economic growth (as you can see in the chart above).

In the mid-1970s, and especially the 1980s, however, the situation changed. The income flowing to everyone but the affluent began to trail economic growth — by a lot.

Why? Labor unions shrank, giving workers less bargaining power. Business executives and investors decided to maximize corporate profits, regardless of the societal effects. The government became more passive about regulating big business. Government also scrimped on investments that create good-paying jobs, like education. And taxes fell much more for the rich than they did for everyone else.