Final answer:
The third largest source of health insurance in the U.S. is not specifically named in the provided information, but the context suggests it could have been covering an approximate figure close to the number of uninsured individuals mentioned at different times, ranging from 26 to 31 million people.
Step-by-step explanation:
The question asks about the third largest source of health insurance in the United States and how many people it covers. Although the provided information does not specify which is the third largest source, it does provide context on the number of uninsured Americans.
Prior to the full implementation of the Affordable Care Act (ACA), also known as 'Obama Care', in 2014, it was reported that nearly 45 million Americans were uninsured. After the ACA came into effect, the numbers dropped significantly, reaching a low in 2016 before rising again. As for the approximate numbers of uninsured individuals, the information mentions various figures ranging over different years.
For instance, in 2019 around 26 million, and then by 2020 the number rose to 31 million. Looking at historical data, the third largest source of health insurance, which is not explicitly named in the provided materials, could have been covering any figure close to these numbers of uninsured people at different points in time.