More than 65 million Americans—about one in five—are enrolled in Medicaid or a government health program for children, according to new federal data.

About 1.1 million of them signed up in April, the Centers for Medicare and Medicaid Services reported. The agency oversees the federal-state Medicaid program and the Children’s Health Insurance Program, or CHIP.

Part of the growth is a result of the Affordable Care Act, also known as Obamacare, the Health and Human Services Department’s blog said.

President Obama’s signature health care law called for all states to relax their Medicaid eligibility requirements to allow for more enrollees. The Supreme Court struck down that requirement, making it a voluntary decision for states.

States that expanded eligibility for their Medicaid program had a greater enrollment growth than in states that didn’t, the HHS blog said: “Enrollment in those states rose by 15.3 percent compared to the average enrollment from July through September while states that have not expanded reported only a 3.3 percent increase in enrollment during that same time period.”

Nina Owcharenko, who heads up health policy research at The Heritage Foundation, said the higher numbers are not a surprise.

“The original Congressional Budget Office estimate of the Affordable Care Act expected half of the uninsured to end up in Medicaid,” Owcharenko, director of Heritage’s Center for Health Policy Studies, told The Daily Signal.

The increasing Medicaid population, Owcharenko said, is “a troubling trend that reflects not only a struggling economy but a deliberate effort—as a result of ACA—to expand the government’s control over health care.”

Supporters of Medicaid expansion say the program helps low-income families while easing the financial burden for hospitals and doctors that treat a higher number of poorer patients.

However, Owcharenko argued that Medicaid has a dismal track record in providing quality care. “Rather than advancing desperately needed reforms in Medicaid, the ACA pushes more people into this failing program,” she said.