Although other awards telecasts and specials throughout this season have seen their ratings surge over last year, with some setting new records, such was not the case with Sunday night's telecast of the Academy of Country Music Awards, in which Carrie Underwood was named Entertainer of the Year. The ACMAs averaged 13.1 million viewers, down 16 percent from the 14.8 million who tuned in to the awards telecast a year ago. Among the key demo of adults 18-49, it was down 18 percent. (Earlier in the evening, CBS's 60 Minutes, which featured Katie Couric's interview with Al Pacino, averaged 10.8 million viewers, down from 15.8 million a week ago. Nevertheless, the figure represented twice the number of viewers that Couric averages for her nightly evening newscast, suggeSting to some that viewers may be more disposed to watching her as an interviewer than they are as a news reader.) ABC also reported significant drops in viewing for its one-time Sunday-night big draws, Desperate Housewives and Brothers and Sisters. Indeed Housewives , which once regularly averaged 20 million viewers or more, could only draw 10.4 million Sunday night. And Brothers and Sisters settled for 7.9 million.