The "7.3 Million"

“The administration finally released the Obamacare enrollment count this week.
Like everything else about their scorekeeping we got a number. Just one number. A number that was conveniently better than we had expected. And, we got no real context for the number or any of the back-up information.
I thought this quote in a Politico article was telling:
The figure is complex to unravel. The number came from the health insurers, who told the Obama administration every month how many people are covered by Affordable Care Act plans. A CMS official said Thursday that in prior monthly reports, the numbers varied widely, but recently stabilized.””