Domestic migration is helping to spark population growth in North Carolina, according to data from the U.S. Census Bureau. About 100,000 more people were living in the state on July 1, 2013, compared with the previous year, and 38% of that increase was due to migration from other states. The increase is a bit puzzling given that the state's job market is not particularly strong, said Keith Debbage, a geographer at the University of North Carolina at Greensboro. "I would suspect and assume that some of that may be the ongoing retirement migration," he said. "I can't imagine that a whole host of people are coming into the state looking for jobs."