WASHINGTON - A report confirms that fewer people than expected are purchasing health insurance under President Barack Obama's health care law.

The Congressional Budget Office study released on Monday says that 13 million people are likely to purchase policies through the Affordable Care Act, down about 8 million from estimates early last year. That's based on updated enrollment figures through last month.

The Department of Health and Human Services had already flagged the lowered expectations last fall, predicting just 10 million customers would sign up and pay premiums through online insurance markets by the end of 2016.

The federal and state markets - also called exchanges - offer subsidized private insurance to people who don't have access to job-based coverage. The budget office says fewer unsubsidized customers are buying through the exchanges.