In case you have a lot of free time, the U.S. Census just issued a 44 page report on the state of health insurance in the U.S. for 2015. This report does not attempt to suggest a cause/effect of the decline in uninsured. It's "just the facts". But the facts are fascinating. You can download a link here:
Key takeaways (in my opinion):
Percent of Uninsured Americans fell 1.3% to an all-time low
29.1 million Americans are uninsured (9.1%) (another all-time low)
Private insurance continues to be the primary source of health insurance over public insurance (e.g., Medicaid, Medicare, etc.) 67.2% vs. 37.1%
The breakdown of the types of insurance for 2015 was:
28.9 % of noncitizen adults were uninsured. This is ~2.5x greater than uninsured American citizens (10.8 %)