WASHINGTON -- Approximately 4 million individuals have now signed up for health care plans under the newly created Obamacare insurance exchanges, a senior administration official told The Huffington Post on Tuesday.

The numbers mean that roughly 700,000 people have signed up for health care plans since the end of January. And with five weeks before the enrollment period deadline at the end of March, they put the administration on pace to come close to the Congressional Budget Office's initial projection that 7 million individuals would sign up for insurance coverage during the period.

"With individuals and families enrolling in coverage every day, we continue to see strong demand nationwide from consumers who want access to quality, affordable coverage," reads a statement from the administration, passed in advance to The Huffington Post. "Consumers are shopping and enrolling in plans on HealthCare.gov every day; system error rates are low and response times are consistently less than half a second. Our call center has handled more than 12 million calls so far and is open 24/7 to assist consumers in English, Spanish and more than 150 languages."

But with the good news remain some questions. The number of people who have signed up for plans and paid their first month's premium remains unknown, though insurers have suggested about 20 percent of individuals have not paid. Moreover, it is unclear how many of those individuals who signed up in February were young and healthy -- the population demographic that the administration needs to ensure that the exchanges have a stable balance of healthy and sick consumers. A senior administration official said that a more detailed report about the enrollees would be released in mid-March.

Nevertheless, supporters of the law will cheer the news that 4 million people have now signed up for the Affordable Care Act, after having watched the botched launch in October in horror. Back then, it was unclear if the enrollment period would have to be delayed in order to accommodate the slow start. There is little such talk today.

The new enrollment number does not include the millions of individuals who have signed up for Medicaid, though it's not known how many of those individuals renewed their prior coverage or how many are new Medicaid recipients.

The news seems likely to get better for supporters of the law in the next month as well. With a looming enrollment deadline, the administration anticipates a rapid increase in people signing up for coverage. They also expect the number of young enrollees to rise rapidly. That was what happened when the state of Massachusetts implemented similar reform in 2007.

According to Bloomberg News: "By November of that year, the last month to sign up to avoid a penalty, the portion of enrollees age 35 or younger had more than doubled to 36 percent from February, one analysis showed."