With its best showing to date, the state's MNsure exchange signed up more than 85,000 people for private coverage during the open enrollment period that concluded on Sunday.

The tally announced Monday exceeds a goal in MNsure's budget of 83,000 enrollees by year's end. It's also more than 40 percent ahead of last year's open.

Republican critics noted, however, that MNsure remains far shy of original projections that suggested 450,000 people would buy private plans through the exchange by 2016.

It's not clear whether MNsure will still exceed the enrollment goal by December, since sign-up tallies at the end of open enrollment typically decline over the year.

"This is a significant increase in the number of people who are signing up for coverage relative to last year," said Cynthia Cox, a researcher with the California-based Kaiser Family Foundation.

"Minnesota premiums have increased, so there might [have been] more people looking for financial assistance," Cox said. Another possible factor, she said, is "the increased penalty for people who go without health insurance."

Minnesota launched the MNsure exchange in 2013 to implement the federal Affordable Care Act, which requires almost all Americans to have health insurance or pay a tax penalty. It's an option for the roughly 300,000 state residents who buy private coverage on their own, outside of employer groups and government programs.

Technology problems with MNsure's launch in 2013 cut enrollment, as did a lack of federal tax credits for Minnesotans. Subsidies depend on the cost of coverage in a region, so low premiums in parts of Minnesota for 2014 and 2015 limited eligibility for tax credits.

This year, the average premium in the individual market is up 41 percent, so MNsure and insurers expected more people would buy through the exchange and qualify for tax credits.

Allison O'Toole, the MNsure chief executive, credited a statewide network of health insurance navigators and brokers with helping connect more Minnesotans with coverage through the exchange. Those partner organizations had more than 2,000 enrollment events.

The state's projections in early 2013 for enrollment are no longer the yardstick for measuring MNsure's performance, O'Toole said during a news conference in St. Paul.

"Right out of the gate three years ago, those projections were just flat wrong," she said. "We've worked really hard … to set realistic goals based on our experience, and based on real data, and that's what we do now."

Rep. Greg Davids, R-Preston, said in a statement Monday that MNsure officials have been "constantly moving the goalposts."

"Based on their first two years, it is unlikely that all of the people who applied through MNsure actually will complete enrollment and receive their insurance cards," Davids said.

About 45 percent of those buying through MNsure this year are new to the exchange. That's a higher share than in many other states, said Cox of the Kaiser Family Foundation, but it's difficult to interpret the figure.

Growth could mean more people here left the ranks of the uninsured for coverage. With strong outreach and bigger penalties in 2016 for lacking coverage, more young and healthy people might have been compelled to buy coverage — good signs for the health of the risk pool, Cox said.

But she pointed out that Minnesota has been unusual in having a large share of individuals buying coverage in the "off-exchange" market, where people purchase through brokers or directly from insurers. So, MNsure's gains might reflect that more of those consumers shifted to the government-run marketplace, perhaps to tap tax credits.

MNsure spokesman Shane Delaney said Monday that exchange officials aren't sure where enrollees came from, although the question could be addressed in the coming months by surveys from other groups.

On Monday, MNsure said it didn't have updated information about the age of people buying coverage, or their choices. Earlier reports suggested more older people were signing up for coverage, along with more buying "bronze" plans with high deductibles.

Twitter: @chrissnowbeck