How many people got new health insurance?

The final numbers are in—well, almost in—and it's clear that a whole lot of Americans enrolled in new health plans during the Affordable Care Act's first open enrollment period, which officially ended on March 31 but in fact went on several weeks longer for a lot of people.

The government issued its official report today of enrollment through April 19, which says that that 8,019,763 people signed up for coverage through their state's official health insurance marketplace—of which nearly half, or about 3.8 million, consisted of procrastinators who waited until the last month to get the job done.

In addition, the government estimates that about 5 million people bought individual health plans through private channels instead of through the state marketplaces.

That's 13 million right there.

And we haven't even gotten to Medicaid, whose total enrollment is up 4.8 million compared with last September, according to a separate report also released today. It's not possible to tell, exactly, what proportion of these new Medicaid recipients are getting "expanded" Medicaid, available to all low-income households in states that offer it, and what proportion are people who applied for private coverage on their state marketplace and found out they had been eligible for other types of Medicaid all along and didn't realize it.

Still, adding all new Medicaid enrollees brings the total to 17.8 million.

Another piece of good news is that the March enrollment surge brought in a whole lot of young and presumably healthy enrollees, which insurance companies need to balance out older, sicker, and more expensive members in their risk pools to keep premiums down. In fact, 52 percent of March enrollees were between the ages of 18 and 34.

But have all these new enrollees paid their first month premiums yet? That's a question skeptics about the new law have asked me a lot, and the answer is that it's too soon to know.

Why? Because there's a time lag between enrolling in coverage on a marketplace and actually paying a premium. What happens is the marketplace sends your information to the insurance company you chose, which then sends you a bill for your first month's premium. People who didn't sign up until the very end of March, or even into April, may not have to pay those premiums until sometime in May.

But we do know that insurance companies nationwide have said that among people who signed up earlier in open enrollment, anywhere from 80 to 95 percent eventually paid their first premiums.

And eventualy we'll know this number for all new enrollees. I'll be sure to pass it along when it comes out.

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—Nancy Metcalf

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