The percentage of Americans without health insurance remained steady at 8.8% in 2017, according to the Census Bureau.

The flat rate was the first time since 2010 that the number of uninsured did not fall since the Affordable Care Act's passage in 2010.

The Census also showed a growing divide between states that took advantage of Obamacare's Medicaid expansion and those that declined the expansion.

The percentage of Americans without health insurance did not decline on 2017, marking the first time since the passage of the Affordable Care Act that the uninsured rate held steady.

According to the Census Bureau, 28.5 million Americans, or 8.8% of the population, went without health coverage in 2017. That number was a slight increase from the 28.1 million Americans without insurance in 2016, though the rate of 8.8% was consistent. The Census Bureau said the increase was not statistically significant.

The Census report also confirmed the growing chasm between states that decided to take advantage of the ACA's Medicaid expansion and those that did not.

The ACA, better known as Obamacare, allowed states to expand Medicaid coverage to people making up to 138% of the federal poverty line. Since then, 31 states and Washington, DC, have adopted the expansion.

"In states that expanded Medicaid eligibility ('expansion states'), the uninsured rate in 2017 was 6.5%, compared with 12.2% in states that did not expand Medicaid eligibility ('non-expansion states')," the Census Bureau said in the report.

In fact, the uninsured rate in states that did not expand Medicaid went up 0.7 percentage points compared to the stable rate in states that did expand Medicaid. Since 2013, the uninsured rate in expansion states is down 7 percentage points, compared to just 5.3 percentage points in non-expansion states.

The flat uninsured rate came in President Donald Trump's first full year in office. Throughout the year, Republicans and the Trump administration attempted to dismantle Obamacare, though multiple bids to repeal and replace the ACA failed.

The administration did take actions that many experts said would destabilize Obamacare's individual insurance marketplaces, including reducing outreach to get people to sign up for plans.

Perhaps most significantly, Republicans repealed Obamacare's individual mandate — the requirement that all Americans get insurance or face a monetary penalty — as part of their tax bill.

Some experts blamed the stall on the meddling by the Trump administration and GOP.

Matt Broaddus, a senior research analyst at the left-leaning Center of Budget and Policy Priorities, pointed to the studies that showed a large swath of the uninsured are eligible for cheap coverage under the ACA as evidence that the uncertainty and lack of outreach were the cause of the stall.

"Last year’s sabotage efforts likely prevented additional coverage gains by creating barriers to obtaining available and affordable coverage," Broaddus wrote. "Roughly 55% of the uninsured are eligible for health insurance coverage with financial assistance under the ACA or other public programs, the Kaiser Family Foundation and the Urban Institute find."

Phillip Klein, the managing editor of the Washington Examiner and conservative healthcare analyst, argued that the stability of the uninsured rate proved that Democrats claims that Trump "sabotaged" Obamacare are overblown.

"Had there been a significant dip, it would have bolstered Democrats' case," Klein wrote. "Now Republicans can argue that despite all of the apocalyptic warnings, the uninsured rate is the same under Trump as it was under Obama."

"Various actions of the Trump administration, such as slashing the ad and outreach budget for Obamacare and ending certain payments to insurers, have been used by Democrats to charge that the Trump administration has launched a concerted effort to sabotage the law. But that is not visible in the numbers," he said.

Larry Levitt, senior vice president at the Kaiser Family Foundation, a nonpartisan healthcare think tank, said the new data is inconclusive to make a determination either way.

"Progress in reducing the uninsured rate was already stalled, pre-Trump," Levitt tweeted Wednesday. "Increases in the number of people uninsured could come this year and next, as changes to the ACA from the Trump administration and Congress take hold."