Jayne O'Donnell

USA TODAY

Nearly 13 million people signed up for health insurance ahead of the Jan. 31 deadline for 2016 on the state and federal exchanges, federal health officials said Thursday.

The numbers represent an increase of 4 million new people enrolled in the 38 states using HealthCare.gov. Of the 9.6 million consumers who got coverage through HealthCare.gov, about 42% were new to the exchange in 2016.

Department of Health and Human Services Secretary Sylvia Burwell called the season a success on a press call, saying it "exceeded our expectations."

Burwell highlighted that 2.7 million of the newly insured were 18 to 34, which represented more new young enrollees than last year.

Supporters of the law were expecting an uptick in enrollment after a strong December and the typical lull over the holidays. About 700,000 people signed up in the last week of January, compared to more than 1 million in the last week of enrollment last year.

Andrew Slavitt, CMS' acting adminstrator, said that was still a strong week and reflected the agency's efforts to move more of the signups into December, which allowed people to start their policies Jan. 1 and gives insurers more time to see who their new clients are.

More than 60% of new enrollees signed up for Jan. 1 coverage, Burwell said.

Charles Gaba, an ACA proponent who tracks enrollment at acasignups.net , adjusted his projections for national enrollment on the state and federal exchanges twice in January from a high of 14.7 million to up to 12.9 million last week due to what he called "underwhelming" enrollment in January."

Health economist John Goodman, who opposes the ACA, was more pessimistic and cited the tens of millions of people who remain uninsured.

"For every person insured in the exchanges there are almost three others who have elected to remain uninsured," says Goodman who runs the Goodman Institute for Public Policy Institute and advises many Republican politicians. "As social experiments go, you have to count that as an overall failure."

Among the concerns about enrollment cited by Goodman are that people who have enrolled so far have tended to be those eligible for the highest subsidies and those who are sick and likely face high medical bills. Despite the administration's new limits on when people are eligible to sign up outside of open enrollment, "people will continue to find ways to game the system."

Several large Insurers have complained that they wound up with sicker-than-usual ACA customers last year because they waited to sign up during special enrollment periods and were sick and then dropped the plans after getting treatment.

The enrollment numbers place the administration on track to meet Burwell's estimate of 10 million people with ACA plans at the end of this year, which includes people who drop plans or have them canceled when they don't pay their premiums. They do fall far short of the Congressional Budget Office's estimate last March that 21 million would have ACA plans on average each month this year, a prediction that Gaba said was "insane."

CBO lowered that projection last month to 13 million, estimating that 11 million of these people would receive subsidies. Millions of those who don't get subsidies will wind up signing up for individual coverage through an insurer, CBO said. ACA enrollment numbers don't reflect purchases that aren't made on the state or federal exchanges.

The lower enrollment than predicted by CBO is also likely due to more people gaining employer-provided coverage with the strengthening economy, Gaba said.

Goodman notes, however, that more than 1 million people will drop coverage by September "if last year is a guide."

Although the administration doesn't plan to release state totals until later, Slavitt did note that several cities and areas did see huge large late surges. These included several Texas cities including El Paso and Corpus Christi, Texas, Yuma, Ariz., and Las Vegas.

In December, 14 states — including Louisiana, North and South Dakota and Tennessee — saw signups during that were at least 20% higher than they were last year at this time.

Several large southern cities saw big enrollment boosts as January drew to a close. Houston, for example, made up for 3.2% of all plan selections for 2015 and is already accounting for 4% — a 27% increase.

Feds seek insurance sign-ups as clock ticks towards enrollment deadline

CMS' enrollment numbers this year reflect people whose plans are canceled if they don't pay premiums or other reasons. Critics contended the government numbers were skewed last year because the agency wasn't able to calculate this until later in the process.

"How many have paid is a legitimate question," says Gaba.

Those who don't have health insurance for 2016 at tax time in 2017 face penalties that start at $695. Slavitt said the agency's marketing emphasis on the penalties clearly boosted enrollment and this, coupled with deadline-consumers, suggests a greater number of healthy new enrollees.