Even as millions of baby boomers approach retirement, the Social Security Administration has been closing dozens of field offices, forcing more and more seniors to seek help online instead of in person, according to a congressional report released Wednesday. The agency blames budget constraints. As a result, seniors seeking information and help from the agency are facing increasingly long waits, in person and on the phone, the report said. Social Security has closed 64 field offices since 2010, the largest number of closures in a five-year period in the agency's history, according to a report by the bipartisan staff of the Senate Special Committee on Aging. In addition, the agency has closed 533 temporary mobile offices that often serve remote areas. Hours have been reduced in the 1,245 field offices that are still open, the report said. More than 47 million people receive Social Security retirement benefits, nearly a 20 percent increase from a decade ago.