Quote Originally Posted by Red Harvest
Quicky stat for you:

"In 2003, approximately 45 million Americans were without health insurance. That is roughly 15 percent of the population of the U.S. Ginsburg contends that the figure would be even higher if not for the recent expansion of Medicaid and the State Children's Health Insurance Program, both of which are government sponsored."

Now this was just the uninsured, not the underinsured.
From here.
Even the most extreme estimate (the Current Population Survey) contains some positive news. One is the fact that one-third of the uninsured, nearly 15 million people, live in households with annual incomes of $50,000 or above. Half of those earn more than $75,000. Moreover, (as noted earlier) 10 to 14 million uninsured people may be eligible to enroll in Medicaid and CHIPs but simply have not done so.

Why is this good news? These data suggest about 60 percent of the uninsured already have access to government health insurance programs or have enough income to afford private coverage.

When these individuals are subtracted from the total, the actual number of uninsured truly lacking access to coverage may be as low as 18 million people, or about 6 percent of the U.S. population. If we further subtract those who are not uninsured for an entire year or more, the number is likely even less.

It is completely plausible that many people willingly choose not to purchase health insurance. For instance, people who qualify for Medicaid can always enroll after they become sick. In addition, the uninsured receive a substantial amount of free medical care and physician services--by some estimates, more than $1,000 worth every year--by government-run, for-profit, and nonprofit health care providers. The availability of free care inadvertently creates an incentive for persons to drop insurance coverage.
That's just an excerpt- anyone that's interested should read the entire article as it looks more closely at how many people are really uninsured, why, and what the term really means.