Nine years after President Barack Obama signed the Affordable Care Act (ACA) into law, the share of Americans who are uninsured remains at a historic low. In California, the uninsured rate remains stable at 8.5% — nearly 50% lower than it was in 2013, before the ACA was implemented. And yet, millions of Californians remain uninsured (PDF), with undocumented adults making up the largest portion of them.