WASHINGTON (AP) — More people sought U.S. unemployment benefits last week, but applications are still at a low level that points to a healthy job market. Many businesses complain they are having trouble finding qualified workers to hire for their open jobs, which probably makes layoffs less likely. Economists at Bank of America Merrill Lynch point out that much of the increase in optimism has occurred among older, middle-income Americans, yet middle-aged, wealthier people drive more spending.