ST. PAUL — MNsure’s record-breaking enrollment for 2017 belies a startling trend in Minnesota’s health insurance market: The number of residents buying coverage on their own is getting smaller.

Nearly 270,000 residents bought insurance on the individual market last year, either on the state exchange or directly though insurance agents of health plans. As enrollment closed this week in Minnesota, that number was down to roughly 190,000, according to the state’s main trade group for health plans.

That likely means more people chose to go uninsured for 2017, scared off by massive premium increases or the uncertainty surrounding the federal health care law in the new Trump administration. Industry experts, state officials and lawmakers fear the smaller pool is a recipe for another year of rising costs unless they step in with new policies.

“I’m concerned with the market shrinking this much that recovery becomes even more difficult,” said Sen. Michelle Benson, a top Republican on health care issues.

The shrinking of the individual market, where shoppers who aren’t covered through employers or public programs buy their insurance, follows a perilous year for Minnesota’s health care system.

The state’s largest insurer, Blue Cross Blue Shield, left the market for 2017, nearly sparking a complete exodus by the remaining plans. To keep them on board, state regulators agreed to massive premium hikes: from 50 percent to 67 percent, on average.