The price of closely watched Obamacare plans will rise 15 percent next year, the Congressional Budget Office said Wednesday in a new report.

The CBO also projects about 5 million more people under the age of 65 will be uninsured in 2027 than it estimated in September, up to a total of 35 million people.

The double-digit premium increase would come during President Donald Trump's third year in office and could add fuel to a heated debate over health care and the fate of the Affordable Care Act, known as Obamacare.

Trump and congressional Republicans tried unsuccessfully to repeal the landmark health law multiple times last year. They managed to repeal the individual mandate, which required most people to have some form of health insurance or pay a tax penalty, as part of the broader tax law it passed in December. The change is slated to go into effect next year.

This coupled with higher premiums will cause 3 million more people than previously forecast to be uninsured next year, CBO estimates. Between 2019 and 2028, it expects the number of uninsured people to increase to 35 million.