An insurance agent from Sunshine Life and Health Advisors, speaks with a woman shopping for insurance under the Affordable Care Act at a store setup in the Mall of Americas on November 1, 2017 in Miami, Florida.

Obamacare sign-ups on the federal health insurance marketplace fell 20% in the first two weeks of the 2020 enrollment season compared with last year, according to new federal data released Wednesday.

In the first nine days of open enrollment, 932,049 people chose a plan for the 2020 coverage year on HealthCare.gov, the federal health insurance exchange that serves much of the United States, according to data published by the Centers for Medicare and Medicaid Services.

That compares with 1,176,232 consumers who selected their coverage through the exchange during the first two weeks, or 10 days, last year, according to federal data released at the time.

More than 680,000 existing customers renewed their coverage on the marketplace, while 244,928 new consumers chose an insurance plan on HealthCare.gov. About 8.5 million people enrolled in Obamacare during last fiscal year.

Open enrollment began Nov. 1 and will run until Dec. 15 for most states. People who do not sign up for an Obamacare plan by the end of open enrollment will not be able to obtain coverage until the fall of 2020, unless they have a so-called qualifying life event, such as getting married or having a child.

The tally comes as a federal appeals court in New Orleans is expected to issue a decision any day now on a lower court ruling that overturned Obamacare, formally known as the Affordable Care Act, in a case known as Texas vs. the United States.

Health and Human Services Secretary Alex Azar has told reporters that 2020 open enrollment will continue even if the 5th U.S. Circuit Court of Appeals upholds the ruling that found the health-care law unconstitutional. The health law was ruled unconstitutional during the final days of open enrollment last year, but the judge in the case issued a stay.

Americans shopping for 2020 health plans will find premiums edging lower for the second straight year, down 4% on average, and more insurers to choose from.

The average premium for a 27-year-old who buys a benchmark silver plan will be $388 a month in 2020 before subsidies, down from the current $406, according to CMS. The number of insurers offering plans on Healthcare.gov rose from 155 last year to 175.

Obamacare exchanges are seeing stability after years of regulatory concerns, said Tara Straw, a senior policy analyst at the Center on Budget and Policy Priorities.

"People understand the value of health insurance, and there are a lot of good deals in the marketplace," she said.

The New Orleans federal appeals court decision is "definitely a concern," Straw said, adding the ruling could cause some confusion among consumers.

This is the second enrollment season since Congress reduced Obamacare's individual mandate fee to $0. The mandate imposed a tax penalty on consumers who went uninsured and was a key part of the health-care law.

Obamacare sign-ups sank 4% year over year during open enrollment last year.

The end of the mandate, along with President Donald Trump's push for cheaper, less comprehensive short-term health plans and a substantial slash in outreach funding, was expected by health policy analysts to put a damper on Obamacare enrollment rates.

Joshua Peck, co-founder of Get America Covered and former chief marketing officer for HealthCare.gov, said technical problems on the site on the first day of enrollment also could have played a role in fewer sign-ups.