South Carolina, California and Michigan suffered the most financial pain in May as unemployment, home foreclosures and bankruptcies rose, according to The Associated Press' monthly analysis of economic stress in more than 3,100 U.S. counties.

The latest results of the AP's Economic Stress Index show the average county's stress score hit 10 in May, from 9.7 in April. In May 2008, the average score was 6.2.

The AP calculates a score from 1 to 100 based on each county's unemployment, foreclosure and bankruptcy rates. The higher the score, the higher the economic stress.

Under a rough rule of thumb, a county is considered stressed when its score tops 11. In May, 36 percent of the counties scored 11 or higher, up from 34 percent in April.

South Carolina counties' scores averaged 15, the third-highest in the latest analysis, behind California and Michigan, whose scores averaged 16 and 15.9.

California has been battered by the housing bust, and Michigan has absorbed the brunt of the auto industry crisis.

"And South Carolina is a little bit of everything," said Sean Snaith, economics professor at the University of Central Florida. "Manufacturing and construction jobs have been hard hit in the state."

The counties of at least 25,000 residents that suffered the sharpest increases in stress scores over the past year were manufacturing communities: Williams County, Ohio; Elkhart County, Ind.; Huntingdon County, Pa.; Howard County, Ind.; Union County, S.C.; and Noble, Ind.

AP's analysis also found that foreclosure rates climbed over the past year in areas hit hardest by the housing crisis: Arizona, California, Florida, Nevada and metro Atlanta.