Picture a room with 100 people in it — just regular adults, people with jobs and monthly bills and credit scores.

In America, if that room contains a sufficient cross section of the population, as many as 40 people will have debt stemming from medical or dental care, according to one national survey. Two out of every five.

Now zoom in and apply that to Colorado, which national data suggests is fairly average when it comes to the number of people with medical debt. That’s potentially well over 1 million adults in the state with outstanding health care bills or medical debt. It’s a population that if it were its own city would be the state’s largest by far.

Medical debt is the most common collection item on consumer credit reports nationally, according to the Consumer Financial Protection Bureau. But it also lurks in other ways — as credit card bills and payment plans and loans needing to be repaid to friends or family.