The number of Mainers enrolling in health care exchanges under the Affordable Care Act continues to grow even with a decision by one insurance cooperative to stop enrolling new clients.

Lewiston-based Maine Community Health Options has the lion’s share of the business in the marketplace created by the health care overhaul, but Harvard Pilgrim and Anthem have good options that will remain after Community Health Options stops accepting new enrollments this month, said Janice Daku, who oversees the state’s health care navigators.

“All of the plans continue to offer the essential health benefits. There will still be good choices for consumers,” said Daku, who works for Western Maine Community Action.

The latest federal figures indicate more than 66,000 people are enrolled under the federal health care law in Maine, and that figure will grow once numbers are tallied for the latest open enrollment period, she said.

While Tuesday marked the deadline for people to sign up for health care insurance that begins on Jan. 1, open enrollment continues through the end of January, officials said.

The healthcare.gov website experienced some delays Tuesday but things were running smoothly overall, said Emily Brostek of Maine Consumers for Affordable Health Care.

“Things are chugging along the way they’re supposed to. We’ve been seeing steady response from consumers looking for help signing up for coverage,” Brostek said.

Part of the growth this year comes from people exploring their options as they realize they’re going to face a bigger tax penalty if they fail to get insurance, officials said.

The penalty in the coming year will grow from $95 to 2.5 percent of household income or $695 per adult and $348 for household members under 18.

Going forward, Community Health Options will continue to offer coverage, but it will no longer accept new customers after Dec. 26 after recording its first operating losses. The announcement this week casts further doubt on the future of co-ops, which are small nonprofit insurers designed to inject competition into insurance markets.

But there are still plenty of offerings in Maine. The number of plans will drop from 31 to 22, Daku said, and Harvard Pilgrim and Anthem remain on solid financial ground.

On Tuesday, Mandy Bolduc of Wilton completed her paperwork on a Harvard Pilgrim plan that will save her $421 per month over her current insurance plan that expires at the end of the year.

She said she wished she’d done it sooner.

“I wasn’t aware that I would save that much money,” said the 53-year-old Bolduc, who’s been paying for insurance under the COBRA health insurance law since her divorce three years ago.