California reported its final Obamacare enrollment figures today, and that just about wraps things up for this year. Via Charles Gaba, here are the final enrollment numbers for the past few years:

Enrollment numbers dropped by about 300,000 from last year, and all of that was due to a decline on the federal exchange. It’s tempting to conclude that the culprit for this is Donald Trump’s efforts to sabotage Obamacare, but the declines began in 2016, when Obama was still in office,¹ and have continued pretty steadily since then. My guess is that they’re most likely due to an improving economy, which has put people back to work and given them access to employer health insurance. This in turn means that every year some number of people will drop out of Obamacare and sign up with their employer plan instead.
But it’s really hard to say for sure. The size of the decline is small (a couple of percent per year); we don’t have Medicaid numbers yet; and as we saw a few days ago, we don’t even know if the total number of uninsured has increased or stayed flat. Given all this, the reason behind the decline on the federal exchange might not even be knowable.
In any case, the size of the year-to-year changes is so small that I wouldn’t worry too much about it. It’s a gnat in the overall health care picture.
¹The 2017 year began in October 2016 and ended in early 2017. That’s all Obama.