These state (where the GOP controls the state government) have decided that the poor don't deserve life-saving health insurance (even though the federal government would pay for it). In these states, health care is not a right. It is a product that only goes to those who have the money to pay for it (or are lucky enough to work for a company that provides insurance). By refusing to expand Medicaid, these states are condemning thousands of people to death each year.
The politicians governing these 8 states (and the other 17 states refusing to expand Medicaid) should be ashamed of themselves -- but sadly, Republican politicians seem to be incapable of feeling shame.
These percentages are from the Gallup Poll. They were determined by interviews of 178,068 nationwide adults conducted between January 2nd and December 29th of 2013. Because of the large sample, the poll has a margin of error of 1 point (although a few less populated states could have a margin of error as high as 4 points).