Pain is notoriously hard to measure—no one can possibly know what it’s really like except for the person experiencing it. But a new large study published in the Journal of Pain at least gives us a better picture of who in the United States is experiencing it.

Researchers from Washington State University analyzed data from the 2010 National Health Interview Survey. Nearly 90,000 people participated in the survey, and of those, almost 7,000 completed a supplement on quality of life and disability, in which (among other things) they reported how frequently they felt pain in the past three months. The researchers classified pain as “persistent” if respondents said they experienced it “most days” or “every day.”

How Often Americans Feel Pain

Chart: The Atlantic, Data: Washington State University

Altogether, about 19 percent of U.S. adults reported experiencing persistent pain in 2010, but the numbers vary widely depending on demographics. Women were slightly more likely than men to have persistent pain, and white people are more likely than Latinos and African Americans. Intuitively, older people reported more pain than younger people. The age group with the highest percentage of persistent pain (about 30 percent) was adults aged 60 to 69, though people aged 70 to 79 and 80 to 89 were also up there, at 28 and 29 percent, respectively. About 8 percent of the 18 to 29 demographic experienced persistent pain.

Face and neck pain were the most common locations for persistent pain, though more than any condition or specific region of the body, persistent pain was associated with disability. Adults who couldn’t work because of a disability reported pain most often, with 60 percent of them experiencing it most days or every day.

Some other findings are about what you’d expect—people who rated their overall health as “fair” or “poor” were more likely to have pain, as were obese people and people who’d recently been to the hospital. And living with persistent pain was associated with higher rates of anxiety, depression, and fatigue.

The researchers point out that their estimate that 39 million adults in the U.S. have persistent pain is much lower than that of a 2011 report by the Institute of Medicine that estimated 100 million Americans with chronic pain. The study suggests the difference is in the definition—“persistence can be seen as a relatively discrete component of the broader construct of chronicity,” the researchers write.

They also acknowledge the difficulty of even studying pain at all, subjective as it is: “A single population survey item cannot hope to capture the complexity of the pain experience,” the study reads. But the researchers suggest that persistence could be one piece of the pain puzzle, and now we know some risk factors for it.