Powered by a late surge, Georgia’s enrollment in the 2015 health insurance exchange easily surpassed the half-million mark.

Federal officials said Wednesday that 536,929 Georgians selected a plan or were automatically re-enrolled in the state exchange. The Affordable Care Act provides for exchanges in all 50 states, and this is their second year of operation.

Open enrollment ended Sunday. The figures show that Georgia enrollment accelerated in the final two weeks, with more than 60,000 signing up. As of Feb. 6, 468,464 had enrolled in coverage in Georgia.

This year’s enrollment number far outpaces last year’s Georgia exchange total of 316,543, and exceeded many projections for the state.

Nationwide, about 11.4 million Americans selected exchange, or marketplace, plans or were automatically re-enrolled, the U.S. Department of Health and Human Services announced. That was 10 percent more than expected, HHS said Wednesday.

Kevin Counihan, the marketplace CEO, said that HHS was pleased about enrollment in the Southern region.

The federal figures show that Georgia’s enrollment was fourth-highest among the 37 states where the exchange is run by the federal government, trailing only Florida, Texas and North Carolina.

Other Georgia statistics include:

** 90 percent of Georgia consumers who were signed up as of Jan. 30 qualified for an average tax credit, or subsidy, of $277 per month through the exchange.

** Georgians could choose from nine insurers in the marketplace in 2015 – up from five in 2014.

** Georgians picked from an average of 41 health plans in their respective counties for 2015 coverage – up from 22 in 2014.

Last year was the debut of the federal exchanges, and due to technical problems they got off to a rocky start. This year’s process has been much smoother.

Bill Custer, a health insurance expert at Georgia State University, said Wednesday that the Georgia enrollment number “is clearly higher than I would have projected for this year.’’

Factors in the increase, he said, include more effort in education and outreach; a better-functioning website; and higher penalties for not having coverage.

Partly due to lack of competition, the southwest Georgia region had some of the highest exchange premiums in the nation last year. This year four insurers offered coverage statewide, instead of just one in 2014.

Danté McKay, the Georgia director for Enroll America, said Wednesday, “We are thrilled that so many Georgians will now experience the security and peace of mind that affordable health insurance ensures.

“Because of the Affordable Care Act, hundreds of thousands in our state will no longer have to make difficult choices like deciding to buy groceries or taking their children to the doctor,’’ McKay added. “The numbers have spoken. The Affordable Care Act is a success.”

Added Cindy Zeldin of Georgians for a Healthy Future: “We’re thrilled to see these numbers, not only for each individual represented within them but also for the impact this will have on our state as a whole.”

The 2015 signup number announced Wednesday isn’t final. Consumers who are already in the process of enrolling in the federal health insurance marketplace will have until Feb. 22 to complete their application, Health and Human Services Secretary Sylvia Burwell said Wednesday.

Fewer than 150,000 people were “in line” to get health insurance coverage through the marketplace, Burwell said at a news conference.

In addition, Wednesday’s figures include individuals who had 2014 coverage but could not continue coverage in 2015 because they did not provide the necessary documentation of their citizenship or immigration status. They will be removed in future reports after their coverage ends on Feb. 28, HHS said.

The HHS media call Wednesday included Atlanta resident Vaughn Alvarez, who said that obtaining ACA exchange coverage allowed him to join a public relations firm that did not offer insurance.

Alvarez said he received “a very nice tax credit’’ and is paying just $80 a month for insurance. “I feel very blessed and very happy,’’ he told reporters.

In addition to ACA exchange signups, the law boosted enrollment for Georgia Medicaid and PeachCare, the state insurance program for uninsured kids.

“Last year, thousands and thousands of people enrolled in Medicaid during the first enrollment who had already been eligible for it but they just didn’t know it,” said Harold Weber, a health navigator, or specialized insurance counselor, at Athens Neighborhood Health Center.

“The ACA helped find these people and helped get them in the system,” Weber said.

The deductible dilemma

While premiums were considered competitive in Georgia and other states, there have been complaints about high deductibles.

In 2015, as in 2014, large numbers of health plans nationwide had high deductibles — the amount that consumers owe before the insurer starts to pay, the New York Times reported in November. This is a big concern for people on low incomes.

In Muscogee County, which includes Columbus, 74 health plans were available on the federal exchange. Fifty-two of the plans had deductibles of $2,500 or more, and 27 had deductibles of $5,000 or more, the Times reported.

Hovering in the background of the strong enrollment report is a pending U.S. Supreme Court ruling on how health care exchanges operate. The court will decide whether it’s legal for customers enrolled in federally run exchanges to get subsidies to defray the cost of the insurance they buy.

Since the exchanges were launched, the federal government has allowed subsidies for consumers in both state-run and federally operated exchanges. But the plaintiffs in the court case say the language of the ACA limits subsidies to state-run exchanges

Currently most exchanges, including Georgia’s, are federally run. If the court invalidates the subsidies in those exchanges, the effect would be far-reaching.

U.S. Sen. John Cornyn (R-Texas) has predicted that the justices will rule for the plaintiffs and thereby undermine the entire ACA.

“What I expect is that the Supreme Court is going to render a body blow to Obamacare from which I don’t think it will ever recover,” Cornyn said recently.

University of Georgia master’s in journalism student Sydney Devine contributed to this article.