By many measures, the U.S. economy is thriving: Unemployment stands close to the 50-year low set in April, the fraction of people age 25 to 54 in work is at a two-decade high, gross domestic product is growing rapidly, inflation is falling, and the S&P 500 is a third higher than it was before the Covid pandemic.

While encouraging, economic statistics like these offer an incomplete picture of the state of the country. There is a deep and persistent national malcontent: In a recent NBC News poll, nearly three-quarters of Americans surveyed said the United States is on the wrong track, and Gallup reported that poor life ratings are at record highs.

What the economic statistics obscure in the averages is that there is not one but two Americas — and a clear line demarcating the division is educational attainment. Americans with four-year college degrees are flourishing economically, while those without are struggling.

Worse still, as we discovered in new research, the America of those without college degrees has been scarred by death and staggeringly shorter life spans.

Almost two-thirds of American adults do not have college degrees, and they have become increasingly excluded from good jobs, political power and social esteem. As their lives and livelihoods are threatened, their longevity declines.

In the 1970s, American life expectancy grew by about four months each year. By the 1980s, it was similar to life expectancy in other rich countries. Since then, other countries have continued to progress, with life spans increasing by more than two and a half months a year.

But the United States has slowly, gradually and then precipitously fallen behind.

These ever-widening gaps have long troubled demographers and prompted three reports from the National Academy of Sciences. The gaps grew wider during the pandemic.

But even before, not only was life expectancy in the United States far from that of the best-performing countries (Japan and Switzerland), but it was also more than two years lower than that of the worst performers (Germany and Britain) among 22 other rich countries.

Public health authorities in the United States record educational qualifications at death so that, after 1992, we can calculate life expectancy by college degree, starting at age 25, when most people have completed their education. In new research using these individual death records, we have found startling results.

Life expectancy at age 25 (adult life expectancy) for those with four-year college degrees rose to 59 years on the eve of the pandemic — so an average individual would live to 84 — up from 54 years (or 79 years old) in 1992. During the pandemic, by 2021, the expectation slipped a year.

But we were staggered to discover that for those without college degrees, life expectancy reached its peak around 2010 and has been falling since, an unfolding disaster that has attracted little attention in the media or among elected officials.

Adult life expectancy for this group started out two and a half years lower, at 51.6, in 1992 — so an average individual would live to nearly 77 years old. But by 2021, it was 49.8 years (or almost 75 years old), roughly eight and a half years less than people with college degrees, and those without had lost 3.3 years during the pandemic.

The divergence of life expectancies on either side of the college divide — one going up, one going down — is both shocking and rare. We have found reference to only one other case in modern history, in the former Communist countries of Eastern Europeafter the collapse of the Soviet Union. Like those countries, the United States is failing its less-educated people, an awful condemnation of where the country is today.

If all Americans had the life expectancy of the college educated, the United States would have been one of the best performers among the rich countries in terms of life expectancy, not the worst. It is the experience of those without college degrees that accounts for America’s failure.

The educational divide is also clear in economic circumstances. Since 1979, wages for those with a B.A. or more far exceeded wages for those with less education. Families without a member with a college degree had a median income that was only 4 percent higher in 2019 than in 1970, compared with 24 percent higher for families where at least one member had a college degree. According to Federal Reserve data, wealth was equally split between those with and without college degrees in 1990, but today three-quarters of wealth is owned by college graduates.

Why is this happening in America? We and others have documented an increase in corporate power relative to workers, which includes the decline of competition, the decline of unions and their ability to raise wages for workers without college degrees and the decreased mobility of workers from less to more successful places.

Other rich countries have been less prone to creating an elite class out of the college educated, while the United States has designed a system that too often works for itself but not for working-class Americans. They have been increasingly excluded from the local and national power that once came with unions and have lost good jobs and wages to excessive health care costs, globalization and automation. Furthermore, the children of the elite rarely serve in the military and increasingly hoard places in top selective colleges.

Unhealthy behaviors are more common among people without college degrees, but those behaviors can often be traced to the environments in which the individuals live, lack of work and community decay. Another factor is those without degrees being targeted by the pharmaceutical industry in the first phase of the opioid epidemic. The destruction of good jobs for less-educated men also helps explain much of the decline in stable two-parent families among non-college-educated men and women. We have also increasingly come to believe that a college degree works through often arbitrary assignation of status, so that jobs are handed out not on the basis of necessary or useful skills but by the use of the degree as a hiring screen.

The divergence with Europe is also striking. European nations generally finance their much less costly health care through government support and not through what is essentially a flat tax on employment (with employer contributions to worker premiums effectively taken out of salary), and Europe’s much broader safety net helps people deal with the disruption of jobs.

Other countries do not have Republican-controlled state legislatures passing corporate-friendly measures — on minimum wages, right-to-work laws, guns, pollution or tobacco taxes — that harm the communities, lives and health of less-educated citizens. Nor do they have Republican governors advising some constituents not to get vaccinated.

As the economy has recovered from Covid, less-educated Americans have been doing better in a tight labor market. What we don’t know is whether this improvement will last or peter out as the market weakens, as happened in the past.

What can be done? We could learn from those European countries that have various educational qualifications that fit different kinds of jobs and lack the sharp binary distinction between those with and without college degrees that is so corrosive in the United States.

We are encouraged by the efforts of both public and private employers to remedy this; it is a low-cost policy that could have large benefits. For example, Gov. Josh Shapiro of Pennsylvania signed an executive order removing the B.A. requirement for 92 percent of state jobs; similar policies are in place in Utah, Maryland, Colorado, Georgia, South Carolina, Virginia, New Jersey and Alaska.

Anything that reduces health care costs would help, as would replacing employer-funded health insurance with vouchers paid for by general taxation. Fighting NIMBYism (residents’ “not in my backyard” opposition to local development) and expanding affordable housing in successful cities would increase mobility. Job creation under the Inflation Reduction Act is a move in the right direction. Working people would do better with stronger unions and fewer hostile measures such as right-to-work laws.

The suffering of less-educated America is not something that must happen, nor is it a necessary price to be paid for progress for the rest of us. Indeed, we find it hard to imagine that an educated elite can prosper indefinitely without a better future for everyone else.