People who want to avoid the tax for lacking health insurance this year are running out of time.

The state's MNsure exchange says more people are calling with questions about coverage, and visiting the MNsure website, in advance of Sunday's deadline for buying private policies for 2015.

Insurers are fielding more calls, too, although they say the current surge isn't as big as in December, when people rushed to get coverage that took effect Jan. 1.

MNsure needs a big bump in sign-ups to reach its private-plan enrollment goal of 67,000 people between Nov. 15 and Feb. 15. At last count, the exchange was about 21,000 sign-ups short with 10 days to go.

"We have our work cut out for us," said Joe Campbell, a MNsure spokesman.

Minnesota was one of more than a dozen states to launch in 2013 its own health insurance exchange marketplace to implement the federal Affordable Care Act. The law requires almost all Americans to have coverage or pay a tax penalty.

Recent data releases for the District of Columbia, Maryland and the federal government's HealthCare.gov website — which is the marketplace for more than 35 states — suggest those exchanges already have seen more private plan sign-ups during the current open enrollment period than last year. MNsure's tally for commercial enrollment last week was slightly behind the total from 2014.

Campbell said comparisons between the states are tricky. Minnesota started with a very small number of uninsured residents, he pointed out, and has public insurance programs that effectively remove potential buyers from MNsure who are buying through exchanges in other states.

He also pointed to media reports from California and Washington that suggest those states are falling short of enrollment targets.

"We are seeing an increase in activity, and we've expected that all along," Campbell said. "We know from limited past experience that people are heavily driven by the deadline, and so we have staffed up appropriately in our call center."

At Portico Healthnet in St. Paul, the nonprofit is offering overtime so there will be enough workers to staff enrollment events this week and weekend, said Rebecca Lozano, a health insurance navigator.

Sunday's deadline does not apply to people with incomes low enough for the state's MinnesotaCare and Medicaid programs. So, navigators are spending more time working with people who need private coverage, Lozano said.

It takes longer to help people consider private policies through MNsure than public insurance plans, Lozano said. That's because some will want to look at spreadsheets and PDFs to compare doctors, hospitals and medications covered by different health plans. As a result, Portico has stretched its enrollment appointments to 90 minutes each.

Some might need that much time to select a plan, Campbell said, but he suggested others could get through in about 30 minutes. The MNsure website, he said, is much more stable than during last year's troubled launch. Even so, some people are still encountering error messages.

"People who are enrolling should read our enrollment tips before they start," Campbell said.

Insurers say they are fielding more calls and seeing more website traffic this week, too. But the volume isn't what it was in December.

"We're seeing a noticeable slowdown of enrollments at our retail store as well as online and over the phone, compared to the high level of activity around the December open enrollment deadline," Jim McManus, spokesman for Blue Cross and Blue Shield of Minnesota, wrote in an e-mail.

Daniel Foss, a spokesman for Bloomington-based HealthPartners, wrote in an e-mail that enrollments have increased since Monday, but "Volumes are between 25 [and] 35 percent of what we saw leading up to the Dec. 31 deadline."