For many years, § 109 of the Federal Credit Union Act provided that "[f]ederal credit union membership shall be limited to groups having a common bond of occupation or association, or to groups within a well-defined neighborhood, community, or rural district." Until 1982, the National Credit Union Administration and its predecessor agencies consistently interpreted § 109 as requiring that the same common bond of occupation unite every member of an occupationally defined credit union. In 1982, however, the NCUA reversed its long-standing policy in order to permit credit unions to be composed of multiple unrelated employer groups. The NCUA thus began interpreting § 109's common bond requirement as applying only to each employer group in a multiple-group credit union, rather than to every member of that credit union. Several banks and the American Bankers Association sought judicial review of this action by the NCUA. They alleged that the NCUA's 1982 interpretation of § 109 was improper and impermissible. Were the banks and the Bankers Association correct?