I got these figures from a British forum, I've no idea what the American ratings are:
3rd Jan - TNA IMPACT (Sat 21:00) 57,000
10th Jan - TNA IMPACT (SAT 2100) 68,000
17th Jan - TNA IMPACT (SAT 2100) 103,000 (highest rated wrestling show of the week in the U.K.; nearest was Smackdown at 76000 and the live Raw at 75000)
24th Jan - TNA IMPACT (SAT 2100) 83,000 (Smackdown did 90000, TNA 2nd, beating live Raw that did 80000)
31st Jan - TNA IMPACT (SAT 2100) 103,000 (Live Raw did 114000, TNA 2nd, beating Smackdown that did 90000)
The comparisons with WWE are a bit flaky, as the audience for RAW will always be largely divided between the live Monday night airing (in the small hours of Tuesday morning) and the more accessible Thursday night slot. SmackDown likewise has multiple "main" timeslots. Although Impact does have replays, Saturday night is
the recognized first-run edition that most TNA viewers will look for.
That said, in its own right this is a fantastic trend for TNA on Bravo. Clearly the new direction led by Hogan and Bischoff is turning heads, and there was of course a live European tour in the middle of this, which may have helped drive the numbers up also.