The number of U.S. workers laid off in May was 47 percent higher than May last year, according to a report by outplacement firm Challenger, Gray & Christmas. The firm reported 93,816 layoffs by U.S. employers in May, up from 63,816 layoffs last May. The total number of job cuts through the end of May was 696,309, an increase of 80 percent from the 385,589 job cuts in the first five months of last year.