The Centers for Medicare and Medicaid Services on Monday said that health care spending rose slowly for the fourth straight year, but said that Obamacare had only a “limited impact.”

Health spending grew at an annual rate of 3.7 percent in 2012, the CMS Office of the Actuary said in a new report. Health expenditures as a percentage of gross domestic product fell slightly to 17.2 percent in 2012 from 17.3 percent in 2011.

“For the second straight year, we have seen overall health care costs grow slower than the economy as a whole. This is good news,” said CMS Administrator Marilyn Tavenner in a statement. “We will continue to work with tools given to us by the Affordable Care Act that will both help us control costs for taxpayers and consumers while increasing the quality of care.”

The agency’s report attributed the low increase in health costs to “slower growth in prescription drug, nursing home, private health insurance, and Medicare expenditures.”

The report also found that “the Affordable Care Act (ACA) contributed to the slow growth for the Medicare program in 2012, but had a limited impact on overall spending as reforms were still being implemented in 2012,” according to a statement.

The annual report on the nation’s health care spending comes amid the botched rollout of Obamacare’s new insurance exchanges.

The administration is well below its enrollment targets and the technical issues marring the launch of the website have weakened public support for President Obama and his signature domestic achievement.

The White House though touted the CMS report and claimed Obamacare had played a role.

“For years, health care costs in America skyrocketed, with brutal consequences for our country,” said Obama health adviser Jeanne Lambrew in a blog post on the White House website. “The Affordable Care Act, for the first time in decades, has helped to stop that trend.

“While there is a debate about how much the Affordable Care Act has contributed to this health cost slow-down, there is no doubt that it reduced Medicare spending growth, and most experts believe that Medicare savings spill over into the private sector,” she added.

Critics say that the slower rate of growth for health expenditures is because of the weak economy, not the president’s health law.

The administration though has made lower health costs a centerpiece of their drive to resell the public on Obamacare.