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Conan O’Brien’s final appearance as host of NBC’s “The Tonight Show” scored big ratings last night. The show not only won its time slot among the younger viewers that advertisers covet, it was No. 1 for the entire evening among all late-night and prime-time programs according to early numbers from NBC.

According to preliminary data from Nielsen Co. provided by NBC, O’Brien’s last show registered a 7.0 rating and a 16 share, compared with “Late Show with David Letterman” with 2.5/5; “Nightline” with 2.8/6; “Jimmy Kimmel Live” with 1.3/4; “Late Night with Jimmy Fallon” with 3.3/10; and “Late Late Show with Craig Ferguson” with 1.5/4. The figures cover only metered markets.

A ratings point represents about 1,149,000 households, or 1 percent of the estimated 114.9 million TV homes in the U.S. The share is the percentage of in-use TVs tuned to a given program.

In addition, O’Brien’s final “Tonight Show” scored a 4. 8 rating among viewers aged 18-49. Its leading late-night competitor, “The Late Show with David Letterman,” scored a 0.6.

O’Brien’s ratings had been soaring in his final week, handily beating some of his late-night rivals. On several nights recently, including Jan. 20 and Jan. 21, O’Brien registered higher numbers at 11:35 p.m. among viewers aged 18-49 than Jay Leno did in his prime-time show, “The Jay Leno Show.”