The seasonally adjusted unemployment rate climbed to 5.2 percent in May, nearing a six-year high as job availability dropped to its lowest level on record, the government said Tuesday.

Rising from 5.0 percent in April, the jobless rate was at its highest point since 5.2 percent in September 2003.

Economists said the latest data suggest it may be just a matter of time before the unemployment rate tops its postwar high of 5.5 percent, recorded in April 2003, despite some positive recent signs of corporate activity.