For many adults, health-care debt is part of their balance sheet — it just may show up differently than expected, new research suggests.

Overall, an estimated 41% of people — or about 100 million adults — currently face such debt, ranging from under $500 (16%) to $10,000 or more (12%), according to a report from the Kaiser Family Foundation. Using $2,500 as a delineation, 56% who carry medical and/or dental debt owe below that amount and 44% owe that much or more.

However, some of it may not have shown up in past estimates or surveys aiming to capture estimates of medical debt. For example, some is on credit cards (17% of adults are paying that way) or is being paid off over time directly to a doctor, hospital or other health-care provider (21%).

“This shows how broad of an impact health-care bills are having on people,” said Liz Hamel, vice president and director of public opinion and survey research at the foundation.