ObamaCare will enroll significantly fewer people than expected in 2016, ending the year with about 13 million customers, the Congressional Budget Office (CBO) said Monday. The figure, which was included in an expansive budget report, is a decline of about 40 percent from last year's enrollment prediction of about 20 million people. The latest projections confirm the Obama administration's previous assessment that fewer people are signing up as the marketplace closes in on its third enrollment season — the final one under President Obama. The new report also underscores the challenges facing the incoming administration in reducing the uninsured rate after 2017.