More than 44,000 Mainers signed up for private health insurance under the Affordable Care Act, according to federal data released Thursday that paints the most complete picture yet of Americans’ efforts to gain coverage under President Barack Obama’s health reform law.

The data reveals a long-awaited, state-by-state tally of individuals who selected private health plans through, the federal government’s gateway for insurance marketplaces in Maine and 35 other states.

From the Oct. 1, 2013, launch of through March 31, 2014, 44,258 Maine residents selected a private health plan through the site, according to the data released by the U.S. Department of Health and Human Services. That’s a swell from 25,412 Mainers at the end of February.

Maine’s tally more than doubled the early goal of 20,000 sign-ups set by grass-roots health advocates, said Wendy Wolf, president of the Maine Health Access Foundation, which organized a statewide enrollment initiative called Enroll 207.

“Maine is always a can-do state,” she said. “We do a lot with so little and this is an example of where neighbor helps neighbor to a degree that I didn’t think, frankly, we’d achieve. But we did.”

The federal report also includes some enrollment activity through April 19, such as individuals who selected plans during a special extension of the open enrollment period and those who experienced life changes that qualified them to sign up later.

Maine emerged as a leader in enrollment, signing up more than 25,000 people for private health insurance through as of March 1. That beat the target set by the Obama administration for the entire open enrollment period, ahead of schedule.

In the end, though, several other states outperformed Maine by signing up higher shares of eligible residents. Vermont topped the list, enrolling 85 percent of those eligible to shop on the marketplace, followed by California, Rhode Island and Florida. Maine enrolled about 36 percent of eligible residents, ranking eighth nationally, according to the Kaiser Family Foundation.

Also called “exchanges,” the marketplaces are geared toward small businesses and individuals who buy their own health insurance rather than receive coverage through work or government programs such as Medicaid and Medicare.

Consumers could access financial subsidies through the marketplaces to help them afford coverage. In Maine, 90 percent of enrollees qualified for tax credits to offset the costs of their monthly premiums or discounts on out-of-pocket costs, according to the data.

The report detailed for the first time the racial and ethnic makeup of Americans signing up for coverage through the federal marketplace. About 63 percent were white, though a third didn’t report their race or selected “other.” Maine had the largest share of whites signing up for coverage at 95.9 percent.

Nationally, more than 8 million people signed up for health plans through and state-run marketplaces, many during a rush in March. The national figure, which Obama heralded on April 18, is well above the White House’s initial target of 7 million sign-ups.

More than 4.8 million Americans enrolled in Medicaid and CHIP coverage through the marketplaces, according to the report.

“Together, we are ensuring that health coverage is more accessible than ever before, which is important for families, for businesses and for Maine’s health and well-being,” outgoing U.S. HHS Secretary Kathleen Sebelius said in a news release announcing the report.

Many of Maine’s enrollees likely turned to after losing coverage through Dirigo Health, the state health insurance program phased out last year, Wolf said.

“I’m excited so many people have the security of having health insurance,” she said.

The Affordable Care Act’s overhaul of the insurance market for those who buy their own coverage relies on healthy Americans, who tend to be younger, signing up to help share the risk with older, sicker consumers and keep costs from skyrocketing.

Nearly 30 percent of enrollees nationally were young adults age 18 to 34, many signing up toward the tail end of open enrollment, according to the new report. In Maine, 22 percent of enrollees fell in that age bracket, an uptick from 19 percent in last month’s report but still among the lowest percentages in the nation.

Insurers still are getting a handle on the relative health of new enrollees, as the Affordable Care Act prohibits them from asking potential customers about pre-existing medical conditions. But carriers selling plans through the marketplace must inform federal regulators in late May or June about premium costs for 2015, which largely rely on the carriers’ ability to predict the medical expenses of the new customers. Many are scrambling to make those calculations, according to Kaiser Health News.

In Maine, a new startup insurer captured the bulk of enrollees, competing against insurance giant Anthem. Maine Community Health Options, a member-run insurance co-op based in Lewiston, enrolled 35,397 Mainers, 80 percent of the state’s total, according to CEO Kevin Lewis. He has attributed the co-op’s success to its competitive premium prices, broad network of health providers across the state, and the appeal of its local, nonprofit roots, among other factors.

Under the Affordable Care Act, everyone must have health insurance this year or pay a penalty, with few exceptions. The penalty is at least $95 but potentially much more, depending on income. Most of those who failed to sign up will have to wait until November for another chance to buy health insurance through the marketplaces.

While many health advocates applauded Thursday’s enrollment figures, the report may not affect Americans’ perceptions of the health reform law. A new poll by the Kaiser Family Foundation found that despite Obama announcing the marketplace exceeded enrollment projections, 46 percent of the public maintains an unfavorable view of the law compared with 38 percent with a favorable opinion.

I'm the health editor for the Bangor Daily News, a Bangor native, a UMaine grad, and a weekend crossword warrior. I never get sick of writing about Maine people, geeking out over health care data, and...