A man holds a sign directing people to an insurance company where they can sign up for the Affordable Care Act.

Obamacare sign-ups fell for a second year to 8.5 million as changes made by the Trump administration to scale back the health-care law took hold and legal challenges left the fate of the Affordable Care Act in question, according to new federal data released Wednesday.

Approximately 8.8 million people signed up for coverage at the same time last year, according to the Centers for Medicare & Medicaid Services. The agency added that the numbers released Wednesday are preliminary and do not represent final fiscal 2019 figures. Enrollment was down more than 10 percent one week prior.

"This Administration has taken strong steps to promote a more competitive, stable health insurance market and these steady enrollment numbers are yet another sign that the Administration's efforts are working," Administrator Seema Verma said in a statement. "With the lowest unemployment rate in 50 years, it's possible that more Americans have employer based coverage, and don't need exchange plans."

Open enrollment, which began Nov. 1, closed Saturday across most of the country. People who didn't sign up for a plan by the end of open enrollment won't be able to obtain coverage until the fall of 2019, unless they have a so-called qualifying life event such as getting married or having a child.

The final open enrollment tally dropped by 4 percent, according to CMS, which oversees the program for 39 states. It wasn't as steep a drop as expected amid rising uncertainty over the future of the ACA, more commonly known as Obamacare. A federal judge in Texas last week said the law was unconstitutional, potentially threatening health-care coverage for millions of Americans and setting up a new legal showdown over former President Barack Obama's signature policy initiative.