Here’s a rare bit of good news: People are living longer than ever.

According to a new Lancet study, life expectancy will jump across much of the industrialized world in the next two decades. By 2030, women in South Korea can expect to live to 90, up from 84 in 2010. Women in France, Japan and Spain on average will hit at least 88 or 89 years, up from around 85. Men in South Korea, Australia and Switzerland will also see big gains, living to about 84 by 2030. Fellows from Canada, Spain, New Zealand and the Netherlands will also make gains.

But one country is stuck treading water: the United States. According to experts who studied 35 countries, Americans will see only a small boost. In 2010, average life expectancy for men here was 76. By 2030, they can expect to live just three more years. For women, life expectancy will jump just two years, from 81 in 2010 to 83 in 2030.

Researchers said our low performance is notable because “life expectancy at birth is already lower than most other high-income countries, and is projected to fall further behind such that its 2030 life expectancy at birth might be similar to the Czech Republic for men, and Croatia and Mexico for women.” It’s worth noting, too, that the researchers only looked at data until 2013 – so they missed the unprecedented decline in life expectancy that hit two years later.

Experts attribute the lag to economic inequality, particularly when it comes to health care. The United States is one of the only industrialized nations without universal health care. “This means that some groups are getting left behind, and it’s pulling the average down,” James Bennett, a researcher in the department of epidemiology and biostatistics at Imperial College London, told Vox.

Americans also suffer higher rates of death from alcohol, drug use and mental disorders. We also have high rates of obesity, homicide and infant mortality, which drags down our average.

South Korea, on the other hand, has done almost everything right. The country’s life expectancy was just 53 in 1960. In the past fifty years, it’s jumped to 82. That’s in large part thanks to an economic boom – gross national income per capita jumped from just $100 in 1960 to $20,045 in 2007. This led to improved nutrition and better health education, as well as a drop in infectious disease, deaths from infant mortality and cardiovascular disease, along with stomach cancer. Also South Korea has fewer smokers than most other industrialized countries.

As Vox explained:

“Bennett pointed out that ‘Korea got a lot of things right’ when it comes to health care access, which is why the increases in longevity have been so widespread. ‘[South Korea] has had economic improvements, which has led to improved nutrition and access to health care and medical technology across the whole population,’ he explained. Unlike the US, ‘South Korea is very equitable, all the way across the population,’ he added.

“What makes this example particularly striking is that on average, citizens in the US are far wealthier than South Koreans – the average income of someone in the US is $55,980, which is more than double the average income in South Korea. But for all its wealth over the past century, the US still hasn’t cracked health.”

Other countries with high projected life expectancy include Australia, Canada and New Zealand. Researchers credit their high-quality health care, along with low smoking and traffic accidents. France and Switzerland did well because they had some of the lowest rates of obesity

Of course, the study is only making predictions based on modeling – the researchers can’t see the future, and can’t account for things like the Affordable Care Act (and it’s impending repeal), epidemics or climate change.