From economist Keith Hennessey comes a really interesting breakdown of how many uninsured people there are in the United States, and how many of those people actually need/want insurance. Since the 46 million number appears prominently in the national health care debate, this information is very valuable.
First, nearly a quarter of the 46 million are already covered by Medicaid or SCHIP, and therefore should not be included. Another 20% are not citizens of the US, while a third are either significantly over the poverty level or are young, single, and childless. If you were to take out these groups from the number of uninsured, the new number becomes 10.6 million, or 2% of the population.
2% just doesn't generate much passion though.