More than 61 million people, or about 19 percent of the U.S. population, were enrolled in Medicaid at the end of the February, the Department of Health and Human Services announced today. The data show a 5.2 percent increase in average monthly enrollment compared with July through September 2013, before some states expanded Medicaid eligibility under the Patient Protection and Affordable Care Act, known as Obamacare.

The administration's plan to extend Medicaid was undercut in June 2012 by a U.S. Supreme Court ruling that allowed states to decide individually whether to expand the program. Enrollment in the 26 states that expanded Medicaid rose by 8.3 percent, compared with 1.6 percent in states that didn't, according to today's report.

"There's no deadline for states to expand, so we're going to keep working with the remaining states as they decide to come on board," Kathleen Sebelius, Health and Human Services secretary, wrote today in a blog post. "Medicaid does not have a set enrollment period so people may be determined eligible for coverage at any time."