About 2.8 million people signed up for Affordable Care Act health plans during an unprecedented, six-month special enrollment period that President Biden ordered to help Americans find insurance coverage during the coronavirus pandemic, according to figures his administration released Wednesday.

The additional enrollees push the reliance on ACA health plans to 12.2 million, the highest level since the insurance marketplaces created under the law first offered health plans in 2014.

The enrollment tally — along with a raft of figures illustrating that such health plans are affordable for many people — comes as the president is pressing Congress to make permanent a temporary upgrade in federal subsidies for ACA plans that began early in the spring through a pandemic relief law.

The final tally, for the sign-ups from mid-February through mid-August, shows that demand for ACA health plans during those months was far below the 8.2 million consumers who chose health plans during the most recent regular enrollment period, which took place during six weeks late last year.

Biden pointed to the record total number of enrollees in a statement accompanying the figures Wednesday, saying Americans who have taken advantage of the special enrollment he ordered “will have more security, more breathing room, and more money in their pocket if an illness or accident hits home.”

The enrollment report, compiled by the Department of Health and Human Services, also shows that in three dozen states relying on the federal insurance marketplace HealthCare.gov, sign-ups were nearly three times greater than those during special enrollments last year and almost four times greater than in 2019.

Before the Biden administration threw the doors wide open, consumers had been allowed to enroll outside the regular, yearly enrollment time only if they had a substantial change in their life, such as the birth of a baby, a move or a lost job. Under former president Donald Trump, who opposed the health-care law, health officials tightened the rules.

Even before Biden created the six months of special enrollment, Americans who became unemployed during the pandemic would have qualified to enroll.

But administration officials have pointed out that such people would have needed to apply for permission, and many did not know they could ask. In addition, administration officials have said the ACA plans were not as affordable for many people until a relief law enacted in March, dubbed the American Rescue Plan, enhanced the tax credits that help most people with ACA coverage pay for monthly premiums.

Wednesday’s report shows that 2.1 million people signed up for new coverage in those states that use HealthCare.gov. In addition, more than 700,000 signed up in 15 states that run their own marketplaces under the ACA. Some of the state-run marketplaces had opened their doors in 2020, soon after the pandemic began, and several have continued.

The 2010 health-care law that created the insurance marketplaces designed them for people unable to get affordable health benefits through a job — a part of the nation’s insurance patchwork that was widely considered unwieldy and overly expensive.

Enrollment in ACA health plans has never become as high as predicted at the outset, when government forecasts anticipated 24 million people would be buying their insurance through the marketplaces after a few years. But Biden has been pressing to extend their reach — and to draw attention to the effects of his efforts. Unlike some Democrats who sought the presidency in 2020 arguing for an expanded role for public insurance, Biden has always embraced the health-care law as the main tool for improving the nation’s health-care system.

And he is urging Congress to build upon the law as Democratic lawmakers are in the midst of debating health-care changes and other safety-net expansions through a budget reconciliation process.

Chiquita Brooks-LaSure, administrator of the Centers for Medicare and Medicare Services, the agency within HHS that oversees the ACA marketplace, acknowledged Wednesday that enrollment never has met the original predictions.

“The ACA over the last decade has really been under attack by many, and that has had an effect,” she said in an interview. “So in investing in outreach, we are . . . reaching communities that still don’t know whether coverage is available.”

Brooks-LaSure noted that the administration is preparing to devote $80 million in grants to enrollment helpers called navigators. That will be the most ever spent and reverses years of cuts by Trump health officials who contended that such enrollment support was ineffective and unnecessary.

“Really trying to make sure people know of their options makes a huge difference,” Brooks-LaSure said, adding that the other central lesson from the special enrollment is, “when you make coverage affordable, people come.”

The administration used the figures released Wednesday to highlight the decision to open the marketplace doors this year has fostered the president’s goal of helping to insure racial and ethnic groups hit hardest in the pandemic. The proportion of Black and Hispanic people who signed up for ACA health plans appears to have been a bit greater than through the limited special enrollments of the past two years, though health officials note that a significant share of the people who purchased the plans did not identify their race or ethnicity.

The figures also show that the proportion of special enrollments among people with middle-class incomes remained small but rose from 2 percent last year to 7 percent during this year’s six-month window. For the first time, the upgraded ACA subsidies allowed tax credits for people with incomes above 400 percent of the poverty level — about $51,000 for a single person, or $106,000 for a family of four.

That change ended years of complaints that ACA plans were unaffordable for people with such incomes because the subsidies were not available to them.

This and other subsidy expansions are scheduled to last two years, unless Congress extends them.