The number of American seeking treatment at community health centers rose by nearly 18 percent from 2008 to 2011 as job losses left more people without insurance, says Reuters, citing a White House report.

The study, released Tuesday, said 20 million Americans used the country’s 8,500 nonprofit community clinics last year—up from 17 million in 2008—and estimated that the number could rise by 1.3 million in the next two years.

Clinics that treat poor and uninsured people in primarily low-income areas are a key element of the president’s health-care law, the future of which is being deliberated by the Supreme Court. The White House has released a series of reports aiming to underscore the value of the reform law.