The number of Americans who bought and began to pay for Affordable Care Act health plans grew slightly this year, despite repeated efforts by the Trump administration to undermine the insurance marketplaces created under the law, new federal figures show.

As of February, a month after the start of 2018 coverage, 10.6 million people had paid premiums for ACA health insurance, about 3 percent more than the year before, according to enrollment analyses released Monday by the Centers for Medicare and Medicaid Services (CMS).

The increase is striking because it happened even though federal health officials last year slashed ACA funding to grass-roots groups that help consumers sign up for coverage, cut advertising and other outreach activities by 90 percent, and shortened the enrollment period by half.

The data shows that, even though the total number of people choosing a health plan for 2018 dipped, a higher proportion of those who picked coverage went on to make a premium payment so that they would actually be insured.

Other parts of the analyses, however, buttress the Trump administration’s contention that the insurance sold through the federal health exchange and similar state-run marketplaces has become unaffordable, especially for people who do not qualify for ACA subsidies.

One of the reports released Monday says that, between 2016 and 2017, the enrollment of people with incomes too high for the subsidies fell by 20 percent, while enrollment fell by just 3 percent for people who could get subsidies. That report does not include figures for this year.

The 2010 health-care law created the first widespread federal help for Americans to afford private insurance, with subsidies of varying amounts available to people with incomes up to four times the federal poverty line — about $48,000 for an individual or about $100,000 for a family of four. The new figures show that 87 percent of people with ACA coverage are subsidized, an increase from previous years.

“The high price plans on the individual market are unaffordable and forcing unsubsidized middle-class consumers to drop coverage,” CMS Administrator Seema Verma said in a statement.

President Trump and senior health-care officials including Verma have used that rationale to make it easier for Americans to gain access to insurance that costs less because it does not provide benefits and consumer protections that the ACA guarantees.

Last month, the Labor Department finalized rules that for the first time allow self-employed people to buy “association health plans,” originally meant for groups of small businesses to band together under certain circumstances to negotiate insurance rates. And health officials are finishing rules intended to expand the use of skimpy, short-term health plans first created as a brief bridge for people between jobs.