President Barack Obama is applauded after signing the Affordable Health Care for America Act during a ceremony with fellow Democrats in the East Room of the White House on March 23, 2010 in Washington, D.C. (Photo by Win McNamee/Getty Images)

NEW YORK (CBSNewYork/AP) — Arizona will be hit the hardest when Obamacare premiums go up next year.

The Department of Health and Human Services revealed Monday that premiums for a midlevel benchmark plan will increase an average of 25 percent across the 39 states served by the federally run online market, and that about 1 in 5 consumers will have plans only from a single insurer to pick from, after major national carriers such as UnitedHealth Group, Humana and Aetna scaled back their roles.

However, in Arizona, unsubsidized premiums for a hypothetical 27-year-old buying a benchmark “second-lowest cost silver plan” will jump by 116 percent, from $196 to $422, according to the administration report.

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But HHS said if that hypothetical consumer has a fairly modest income, making $25,000 a year, the subsidies would cover $280 of the new premium, and the consumer would pay $142. Caveat: if the consumer is making $30,000 or $40,000, his or her subsidy would be significantly lower.

Sen. John McCain, R-Ariz., called the Affordable Care Act a “failure.”

“Arizona families are demanding affordability, accessibility and choice when it comes to their health care – not the expensive, restrictive and poor quality care that has been forced upon them by Obamacare,” McCain said in a statement. “Until President Obama and Congressional Democrats wake up to the law’s failure, and until we repeal and replace it with solutions that encourage competition and put patients back in charge, the Washington-knows-best approach will continue to unfairly burden the Arizona families it was supposed to help.”

Obama administration officials are stressing that subsidies provided under the law, which are designed to rise alongside premiums, will insulate most customers from sticker shock. They add that consumers who are willing to switch to cheaper plans will still be able to find bargains.

“Headline rates are generally rising faster than in previous years,” acknowledged HHS spokesman Kevin Griffis. But he added that for most consumers, “headline rates are not what they pay.”

The vast majority of the more than 10 million customers who purchase through HealthCare.gov and its state-run counterparts do receive generous financial assistance. “Enrollment is concentrated among very low-income individuals who receive significant government subsidies to reduce premiums and cost-sharing,” said Caroline Pearson of the consulting firm Avalere Health

But an estimated 5 million to 7 million people are either not eligible for the income-based assistance, or they buy individual policies outside of the health law’s markets, where the subsidies are not available. The administration is urging the latter group to check out HealthCare.gov. The spike in premiums generally does not affect the employer-provided plans that cover most workers and their families.

Republicans, including Donald Trump, are united in calling for complete repeal, but they have not spelled out how they would address the problems of the uninsured.

Hillary Clinton has proposed an array of fixes, including sweetening the law’s subsidies and allowing more people to qualify for financial assistance.

The law makes carrying health insurance a legal obligation for most people, and prohibits insurers from turning away the sick. It offers subsidized private plans to people who don’t have coverage through their jobs, along with a state option to expand Medicaid for low-income people.

Largely as a result, the nation’s uninsured rate has dropped below 9 percent, a historically low level. More than 21 million people have gained coverage since the Affordable Care Act passed in 2010.

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