In August, the CBO estimated that figure at 4 million.

"The revision is the net effect of several considerations, with the largest factor being the reduction in marginal tax rates, which reduces the tax benefits associated with health insurance provided by employers," the report said.

The report still shows employment as the largest source of health insurance in 2023, at 167 million of 288 million non-elderly people. Currently employment-based coverage accounts for 154 million of 272 million people.

By contrast, the report expects that in 2014, 7 million people will purchase insurance via the PPACA insurance marketplaces (formerly called exchanges), rising to 13 million in 2015 and 24 million in 2016. By 2023, about 25 million people are expected in the marketplaces, with only 4 million of them purchasing employer-based coverage through the marketplaces and only 5 million of them unsubsidized.