The U.S. added 138,000 jobs in May, fewer than expected, the Labor Department reported on Friday. Economists surveyed by Reuters had predicted job gains of 185,000. The unemployment rate inched down to 4.3 percent, its lowest level since 2001. Hourly wages rose by 0.2 percent to $26.22, keeping the year-on-year pay rise at 2.5 percent. Despite the lower-than-expected job gains, the report reaffirmed the argument that the economy is gaining enough strength for the Federal Reserve to raise interest rates again at its June 13-14 meeting, as unemployment has now been below 5 percent for more than a year, suggesting near full employment.