46 million (or 8.2 million) Americans without health insurance?

It's a sobering reality, but healthcare is simply unaffordable for too many people in this country. How can we allow 46 million people to live without health insurance? Do we really have 46 million people who lack health insurance? We can break that number down to some groups, including:

• 14 million are eligible, but do not participate
• 7 million illegal immigrants
• 7 million choose to skip coverage (typically younger adults)
  
• Many without insurance for less than 1 year

So how many people are truly uninsured? Is the number really 46 million or 8.2 million (long-term uninsured, according to one industry study)?