All ratings data from TV by the Numbers.
Sept. 17, 2009: ‘Gossip’
Overnight ratings: 8.1 million viewers, 4.0/11 rating/share 18-49.
Placement: 1st place, leading Fringe, CSI, Grey’s Anatomy, and Supernatural in rating/share 18-49.
Sept. 25, 2009: ‘The Meeting’
Overnight ratings: 7.33 million viewers, 3.8/10 rating/share 18-49.
Placement: 3rd place, behind season premieres of Grey’s Anatomy and CSI in rating/share 18-49.
Oct. 1, 2009: ‘The Promotion’
Overnight ratings: 7.28 million viewers, 3.7/10 rating/share 18-49.
Placement: 3rd place, behind Grey’s Anatomy and CSI in rating/share 18-49.
Oct. 8, 2009: ‘Niagara’
Overnight ratings: 9.10 million viewers, 4.5/12 rating/share 18-49.
Placement: 2nd place, behind Grey’s Anatomy in rating/share 18-49.
Oct. 15, 2009: ‘Mafia’
Overnight ratings: 8.08 million viewers, 4.0/10 rating/share 18-49.
Placement: 2nd place, behind Grey’s Anatomy in rating/share 18-49.
Oct. 22, 2009: ‘The Lover’
Overnight ratings: 8.52 million viewers, 4.2/11 rating/share 18-49.
Placement: 2nd place, behind Grey’s Anatomy in rating/share 18-49.
Oct. 29, 2009: ‘Koi Pond’
Overnight ratings: 8.14 million viewers, 4.2/10 rating/share 18-49.
Placement: 3rd place, behind the World Series Game 2 and Grey’s Anatomy in rating/share 18-49.
Nov. 5, 2009: ‘Double Date’
Overnight ratings: 7.94 million viewers, 3.9/10 rating/share 18-49.
Placement: 2nd place, behind Grey’s Anatomy in rating/share 18-49.
Nov. 12, 2009: ‘Murder’
Overnight ratings: 8.05 million viewers, 4.2/10 rating/share 18-49.
Placement: 2nd place, behind Grey’s Anatomy in rating/share 18-49.
Nov. 19, 2009: ‘Shareholder Meeting’
Overnight ratings: 7.43 million viewers, 3.7/9 rating/share 18-49.
Placement: 2nd place, behind Grey’s Anatomy in rating/share 18-49.
Dec. 3, 2009: ‘Scott’s Tots’
Overnight ratings: 8.05 million viewers, 4.1/11 rating/share 18-49.
Placement: 1st place, leading Private Practice and Fringe in rating/share 18-49.
Dec. 10, 2009: ‘Secret Santa’
Overnight ratings: 9.24 million viewers, 4.4/12 rating/share 18-49.
Placement: 1st place, leading CSI and Fringe in rating/share 18-49.
Jan. 21, 2010: ‘The Banker’
Overnight ratings: 7.29 million viewers, 3.7/9 rating/share 18-49.
Placement: 2nd place, behind Grey’s Anatomy in rating/share 18-49.
Feb. 4, 2010: ‘Sabre’
Overnight ratings: 7.36 million viewers, 3.8/10 rating/share 18-49.
Placement: 2nd place, behind Grey’s Anatomy in rating/share 18-49.
Feb. 11, 2010: ‘The Manager and the Salesman’
Overnight ratings: 7.40 million viewers, 3.7/10 rating/share 18-49.
Placement: 3rd place, behind CBS Survivor: Heroes vs. Villains and Grey’s Anatomy in rating/share 18-49.
Mar. 4, 2010: ‘The Delivery’
Part 1:
Overnight ratings: 8.71 million viewers, 4.5/12 rating/share 18-49.
Placement: 1st place, leading Grey’s Anatomy and CSI in rating/share 18-49.
Part 2:
Overnight ratings: 9.35 million viewers, 4.9/13 rating/share 18-49.
Placement: 1st place, leading Grey’s Anatomy and CSI in rating/share 18-49.
Mar. 11, 2010: ‘St. Patrick’s Day’
Overnight ratings: 7.50 million viewers, 3.8/11 rating/share 18-49.
Placement: 2nd place, behind Grey’s Anatomy in rating/share 18-49.
Mar. 18, 2010: ‘New Leads’
Overnight ratings: 7.63 million viewers, 3.6/10 rating/share 18-49.
Placement: 2nd place, behind NCAA Basketball March Madness in rating/share 18-49.
Mar. 25, 2010: ‘Happy Hour’
Overnight ratings: 7.16 million viewers, 3.5/10 rating/share 18-49.
Placement: 3rd place, behind NCAA Basketball March Madness and Grey’s Anatomy in rating/share 18-49.
Apr. 22, 2010: ‘Secretary’s Day’
Overnight ratings: 6.41 million viewers, 3.3/9 rating/share 18-49.
Placement: 1st place, leading CSI and Private Practice in rating/share 18-49.
Apr. 29, 2010: ‘Body Language’
Overnight ratings: 7.09 million viewers, 3.6/11 rating/share 18-49.
Placement: 2nd place, behind Grey’s Anatomy in rating/share 18-49.
May 6, 2010: ‘The Cover-Up’
Overnight ratings: 6.85 million viewers, 3.5/10 rating/share 18-49.
Placement: 2nd place, behind Grey’s Anatomy in rating/share 18-49.
May 13, 2010: ‘The Chump’
Overnight ratings: 6.575 million viewers, 3.4/10 rating/share 18-49.
Placement: 2nd place, behind Grey’s Anatomy in rating/share 18-49.
May 20, 2010: ‘Whistleblower’
Overnight ratings: 6.60 million viewers, 3.4/10 rating/share 18-49.
Placement: 2nd place, behind Grey’s Anatomy in rating/share 18-49.
Key
More viewers than previous episode
Less viewers than previous episode
You can find Nielsen ratings of other seasons here.