Expanded health insurance coverage under the Affordable Care Act, President Barack Obama’s signature legislative legacy, will cost the government more, according to an official study released Thursday. Still, on balance, the measure more than pays for itself.

The nonpartisan Congressional Budget Office said the health care law will cost $1.34 trillion over the coming decade, $136 billion more than the CBO predicted a year ago. That 11 percent hike is mostly caused by higher-than-expected enrollment in the expanded Medicaid program established under the law.

All told, 22 million more people will have health care coverage this year than if the law had never been enacted, CBO said. The measure’s coverage provisions are expected to cost $110 billion this year.