Fast National ratings for Wednesday, October 3, 2012.
 
Coverage of the first presidential debate between Mitt Romney and Barack Obama filled two primetime hours for most of the networks in most of the country, while it was "Survivor" helping CBS to an overall win and "X Factor" carrying FOX with young viewers on Wednesday.
 
Note, of course, that with the debates airing live, all of these numbers are especially preliminary and subject to change, except for The CW, which doesn't believe in debates.
 
For the night, FOX averaged a 3.1 rating among adults 18-49, beating CBS' 2.8 rating, NBC's 2.7 rating and ABC's 2.6 rating in the key demographic. The CW averaged a 0.6 key demo rating for Wednesday.
 
Overall, though, CBS averaged an estimated 9.74 million viewers and a 6.1 rating/9 share, beating ABC's 5.5/8 and 8.765 million viewers for Wednesday primetime. FOX averaged a 4.7/7 and 8.06 million viewers compared to NBC's 5.1/8 and 8 million viewers. The CW averaged a 0.8/1 and 1.36 million viewers. 
 
8 p.m. - In the only hour of primetime unlikely to be impacted, CBS' "Survivor: Philippines" averaged 10.485 million viewers to win 8 p.m. overall, coming in second with a 2.9 rating among adults 18-49. FOX's "The X Factor" averaged 9.26 million viewers and a 3.4 key demo rating, both up from last week. ABC was third with "The Middle" (7.93 million and a 2.2 key demo) and "The Neighbors" (6.61 million and a 2.2 key demo rating), which beat NBC's comedy block of "Animal Practice" (5.22 million viewers and a 1.5 key demo) and "Guys with Kids" (5.5 million and a 1.8 key demo), which both avoided drops from last week. The CW's finale of "Oh Sit!" averaged 915,000 viewers and a 0.3 key demo rating.
 
9 p.m. - ABC's debate coverage won the 9 p.m. hour overall with 10.29 million viewers and finished tied for second with a 3.0 rating among adults 18-49. CBS' debate coverage averaged 10.24 million viewers and the same 3.0 key demo rating. While NBC's coverage was third overall with 10.01 million viewers, the network was first with a 3.5 key demo rating. FOX trailed on the debate side with 6.87 million viewers and a 2.8 key demo rating. The CW's season premiere of "Supernatural" averaged a strong 1.8 million viewers and a 0.8 key demo rating.
 
10 p.m. - ABC's debate coverage stayed first overall for 10 p.m. with 8.74 million viewers and came in second with a 2.6 rating among adults 18-49. NBC's debate coverage moved up to second overall with 8.64 million viewers and won with a 3.0 key demo rating. CBS averaged nearly 8.5 million viewers and a 2.5 key demo rating in third.
 
All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change, particularly in the case of live events.