Washington area companies kept up their robust hiring last month, especially at professional service firms, construction sites, restaurants and stores, according to Labor Department data released yesterday.

The region added 79,300 jobs in the year ended in May, more than any other metropolitan area and about the same rate of local job creation as in the year ended in April. The region's unemployment rate rose marginally to 3 percent in May from 2.9 percent in April, though that number is not adjusted for seasonal variations and likely reflects college students entering the job market last month.

"The students all come onto the job market in the span of a few weeks, and that pushes up the unemployment rate until they can find jobs," said William F. Mezger, chief economist for the Virginia Employment Commission.

Job creation in the region remained concentrated in a few industries. Professional and business service firms, a category that includes many large government contractors, added 29,700 jobs in the year ended in May. Construction companies added 12,700 jobs. Retailers added 12,800 jobs, and restaurants and bars added 6,900 jobs.

"This is a nation at war, and Washington has always done particularly well during periods of war," said Charles W. McMillion, president of economic consultant MBG Information Services in the District. "Talent is coming from all over the country because they know they can find a job, and that's helping construction and retail and a range of industries."

Some of the industries most hurt by the economic slump that began in 2001 showed little sign of rebound, however. The number of air transportation, telecommunications and manufacturing jobs was little changed in the year ended in May. "They seem to be virtually neutral," Mezger said.