Skyrocketing premiums in the state's individual health insurance market have driven a record number of Minnesotans to enroll in private coverage through the MNsure exchange.

MNsure announced Monday that 103,578 people signed up for private health plans through the exchange thus far, a tally that exceeds by about 20 percent last year's open enrollment total of 85,390.

Surging enrollment through the exchange was expected since shoppers who buy via MNsure can tap federal tax credits that discount their out-of-pocket costs.

But the sign-up tally announced Monday marks the first time that MNsure enrollments have hit the six-figure mark.

"It's really a milestone for us," said Allison O'Toole, the MNsure chief executive. "It means Minnesotans are getting the benefits of shopping through MNsure."

Thus far, 62 percent of private health plan enrollees for 2017 are receiving tax credits year, O'Toole said. The average credit is $672 a month or $8,000 a year — roughly three times higher than the average subsidy last year.

Tax credits are available to subscribers at certain income levels.

The subsides insulate some shoppers from premiums that are jumping by an average of 50 percent or more. Regulators granted such large rate hikes so that health insurers wouldn't entirely abandon the state's individual market for 2017. Insurers have seen mounting losses in the market, which is undergoing fundamental changes under the federal Affordable Care Act (ACA).

MNsure is an option for the roughly 250,000 Minnesotans who last year were buying individual policies. The health plans cover self-employed people and those who don't get coverage from an employer or government program.

Minnesota launched the MNsure health insurance exchange as part of the ACA, which called for online marketplaces where individuals could sign up for private coverage.

The individual market in Minnesota and many other states hasn't grown as expected, despite the health law's tax credit subsidies as well as tax penalties for those who lack coverage. Low premiums in Minnesota plus the availability of generous public health insurance coverage mean relatively few state residents have qualified for tax credits in the past.

The sign-up tally remains a far cry from original enrollment projections, said Rep. Greg Davids, R-Preston.

A consultant in 2013 estimated that more than 400,000 people would be buying private coverage through MNsure by the end of last year.

Plus, Davids said he questions all of MNsure's figures given past troubles.

Davids noted that MNsure is working through a backlog of more than 10,000 cases where subscribers have reported a "change in circumstance" — things like income fluctuations — that could impact their eligibility for subsidies.

"It's dead," Davids said of MNsure. "It just doesn't know it yet."

Christopher Snowbeck • 612-673-4744

Twitter: @chrissnowbeck