A report released by the White House said 20 million Americans now receive healthcare services through 8,500 community health centers, up from 17 million four years ago.
"Those numbers really took a big jump," Mary Wakefield, who heads the U.S. Health Resources and Services Administration, told reporters. "A lot of those folks were people who, when they lost their jobs early on, lost their coverage."
The administration said health centers were able to accommodate larger numbers of patients because of funding provided by President Barack Obama's embattled healthcare reform law and the administration's earlier economic stimulus package.
The report, the latest in a series of government releases aimed at underscoring the value of healthcare reform, surfaced as the U.S. Supreme Court deliberates about the future of the law known as the Patient Protection and Affordable Care Act.
Community health centers, which often serve low-income areas where there are few doctors or hospitals, provide a cornerstone for the law's goal of expanding healthcare access to more than 30 million uninsured Americans.
The ranks of the uninsured, which equaled 1-in-4 Americans last year, pose major social and financial challenges for the $2.6 trillion U.S. healthcare system.
But the high court could overturn the reforms in a ruling expected next month, ending the administration's plans to expand coverage and much of its support for community health centers.
The law also faces repeated election year calls for repeal from Republican politicians who call it government over-reach and a potential drag on the economy.
The administration also announced on Tuesday that it had awarded $728 million in grants for about 400 renovation and construction projects at community health centers. Officials said the funding would allow another 860,000 people to gain access to medical services.
Community health centers are nonprofit groups that serve patients with low incomes, including people with no insurance, limited English proficiency, migrant and seasonal farm workers, the homeless and people living in public housing.
All told, the Obama administration has now allocated $1.5 billion to support major construction and renovation projects at community health centers.
The ranks of health center patients are expected to grow by another 1.3 million people over the next two years, the White House report said.
(Editing by Vicki Allen)