The enthusiasm consumers showed on Black Friday waned in the week following the traditional start to the holiday shopping season. Although chain store sales rose 3.1 percent for the week ended Dec. 2 compared to the year ago period, chain stores saw a 2.6 percent drop in sales compared to the prior week, according to data compiled by International Council of Shopping Centers Inc. and UBS Securities. “Through this past Sunday, consumers shopped less and completed less of their total expected holiday spending than even last year,” said Michael Niemira, chief economist for the ICSC. The national data would seem to indicate that shoppers might be holding out for bargains.