WASHINGTON — The Obama administration said Thursday that 7.3 million people who bought private health insurance under the Affordable Care Act had paid their premiums and were still enrolled.

Marilyn B. Tavenner, the administrator of the Centers for Medicare and Medicaid Services, disclosed the latest count at a hearing of the House Committee on Oversight and Government Reform.

President Obama had announced in April that eight million people had signed up for coverage in the federal and state insurance exchanges, also known as marketplaces.

The chairman of the committee, Representative Darrell Issa, Republican of California, asked why the reported enrollment had dropped by 700,000 people, or about 9 percent.