Thursday ratings: Bush and Grissom say goodbye

UPDATED: Thursday's ratings were marked by the twin farewells of President Bush and Gil Grissom, with the president's departure drawing fairly average viewership and William Petersen's final episode of "CSI" attracting potentially season-high crowds.

William Petersen's final episode as a regular cast member of “CSI” was seen by 24.3 million viewers -- the series' largest audience since the show's 2007 premiere. "CSI" received a 6.6 adults 18-49 rating and a 16 share. “Eleventh Hour” (13.2 million, 3.4/9) also performed well, its second-largest audience of the season.

Bush’s live address totaled a 20.9 metered-market household rating across four networks, which is in the rough ballpark of 25-33 million viewers and doesn't count cable news coverage. 

The speech had to compete with news coverage of the US Airways crash, which seemed like an oddly appropriate bookend to his presidency (a sort of inverse Sept. 11, with another commercial aircraft crashing in New York City, only this time the event concluded wonderfully).

ABC’s “Grey’s Anatomy” (13.1 million, 5.3/12) and “Private Practice” (8.5 million, 3.3/8). “Grey’s” was up a notch from its last series-low original and “Practice” maintained its debut retention of the "Grey's" audience.

NBC's “The Office” (8.5 million, 4.4/10) and “30 Rock" (6.6 million, 3.2/8) were on par, with “ER” (7.0 million, 2.7/7) on the low side.

Fox had a modestly rated second-season finale for “Kitchen Nightmares” (4.4 million, 2.0/5) at 9 p.m.

On the CW, "Smallville" (4.3 million, 1.8/5) had its best performance since November, followed by "Supernatural" (3.0 million, 1.2/3).