The most recent available data show that 46.3 million people had no health insurance in 2008. More than 4 out of 5 (83%) of the uninsured are adults between 18 and 64 (38.3 million in 2008). Children are the next largest group of the uninsured (almost 16% or 7.3 million). Thanks primarily to Medicare, only about 1% of the uninsured are 65 or older (0.6 million). Almost three-quarters (73% or 34.0 million) of the uninsured were born in the United States. Of the 12.3 million immigrants without health insurance, more than half (6.3 million) are working, and about 900,000 are children.