During the first four days of Obamacare's open enrollment 601,462 people signed up for health insurance coverage through the federal healthcare.gov website, according to data from the Centers for Medicare and Medicaid Services.

Making direct comparisons to last year's open enrollment is difficult because there aren't perfectly comparable numbers, but it would appear open enrollment is off to a strong start. Last November, about 1 million people signed up for coverage over 12 days, meaning the current pace of signups appears faster. That said, the open enrollment period is half as long this year at just six weeks, so there will be less time for people to sign up for coverage.

Customers who don't get coverage through a job or through a government program like Medicaid have until Dec. 15 to sign up through the federal government, which for most enrollees is subsidized through tax credits paid for by the federal government.

Democrats have accused the Trump administration of trying to sabotage Obamacare because it has cut the budget for navigators and advertisements on open enrollment in addition to reducing the sign-up period.

Within the total signups, 464,140 customers were renewing customers who already have a plan through the exchange and 137,322 are new customers. The evaluation includes only signups on healthcare.gov, which 39 states use, and therefore does not have information about the other states that run their own exchanges.

The healthcare.gov call center received 527,046 calls in the first week, according to CMS.