Some 45 million people tuned into all or a part of CBS’ “An American Reunion: The 52nd Presidential Inaugural Gala,” according to estimates, giving the network a considerable boost over its normal Tuesday night fare.Meanwhile, Fox Broadcasting’s first Tuesday night schedule fared well when compared to what the network’s stations normally do that evening, though neither of its programs did better than fourth for the timeslot in household ratings. According to A.C. Nielsen overnight statistics, CBS’ special averaged a 22.0/ 34 for its two hours and five minutes on the air, a figure that is considerably higher than the web normally generates with its movie schedule. The program, which featured the reunion of Fleetwood Mac and appearances by Michael Jackson and Barbra Streisand, won each half hour it was on and led in all of the major adult demographics. The inaugural program drew its largest share of the audience from 10:30-11 p.m., when the show recorded a 24.9/41, while its competition on ABC and NBC were drawing in the single digits. CBS’ “Rescue 911,” airing from 8-9 p.m., notched its second-highest rating of the season with a 16.2/24 and led in the key male demographics. Both of Fox’s new entries, “Class of ’96″ and “Key West,” averaged a 6.0/9 for their respective hours. While the shows never challenged on pure household ratings, they were competitive in the younger demographics. Indeed, between 8-9 p.m., Fox was third among the 18-34 set. And the programs were consistent in their ratings on a half-hour basis throughout the night. Nonetheless, Fox’s Tuesday schedule was 43% higher in rating and 50% in share when compared to the same night a year ago on the Fox station lineup. On the night, CBS was first, averaging a 20.0/30, with ABC following at a 13. 2/20. NBC was third with a 8.0/12 and Fox settled in fourth for the night with a 6.0/9.