As he is getting ready to take on daytime with his new syndicated talk show next fall, Anderson Cooper’s primetime fortunes are falling. His CNN show Anderson Cooper 360 is wrapping 2010 as its lowest rated year ever in primetime among adults 25-54 and second lowest in total viewers behind only its primetime debut in 2005. Year-to-year, Anderson Cooper (665,000 viewers, 207,000 in 25-54) is down 33% in 25-54 and 32% in total viewers. Cooper’s declines are not isolated as they mirror CNN’s 34% year-to-year drop in total viewers and 25-54. In primetime, 2010 marks the cable news network’s lowest-rated year in both categories in at least 14 years. Still, Cooper’s sharp ratings declines would probably give a pause to Warner Bros., which produces and distributes his daytime talk show, Anderson. For comparison, Nancy Grace, who hosts a primetime show on CNN’s sibling channel HLN, was on the rise, hitting all-time-high ratings last year when she was signed on to do a syndicated show. Her Swift Justice with Nancy Grace has been the highest-rated first-year syndicated series this season.