Working families are paying much more for health insurance this year, with many postponing doctor’s visits, treatments or filling prescriptions. The number of uninsured Americans is rising as more people wrestle with unpaid medical bills.

This is the stark picture emerging from two surveys released Thursday that show how millions of people in the United States are struggling to keep up with sharply climbing medical costs in recent years.

As the midterm elections approach, Americans are ranking health care near or at the top of their financial concerns, according to a recent poll from KFF, a nonprofit health research group.

Roughly six in 10 adults reported they were very or somewhat worried about affording care.

The majority of Americans — about 157 million — get insurance through their employer. But as costs for coverage have spiked, with increases in the high single digits, businesses have been shifting much more of the additional expenses onto their workforces.

Employees are paying more for coverage, especially if they work for a small business, according to KFF, which released its annual survey of employers about their health benefits.

Many people are also paying thousands of dollars in medical expenses when they get sick, because companies have increased the plans’ deductibles to offset increases in premiums.