The tally includes both sign-ups on the exchange run by the federal government for 39 states, which was released on a provisional basis late in 2017, and on the 12 other exchanges run by Washington, D.C. and the remaining states.
CMS said the average premium before tax credits in 2018 is $621 a month, an increase of more than 30 percent from last year.
However, those receiving tax credits - around 83 percent of consumers on Obamacare - will pay around $89 a month on average in premiums, the agency said. That is down 16 percent from $106 a month last year.