- Marc Berman, Mediaweek

NEW YORK Midway through the November 2008 sweeps, three networks -- ABC, CBS and NBC (yes, NBC!) -- are sharing leadership, according to Nielsen Media Research data. 

CBS is the most-watched network (with 470,000 more viewers than second-place ABC).  ABC is first in adults 18-49 and adults 25-54. And ABC and NBC are tied for No. 1 among adults 18-34. 

But all three networks are down year-to-year. The biggest loser is Fox, which finished fourth in three of the four surveyed categories (excluding adults 18-34), and is down by margins of 15 to 19 percent. Excluding a flat performance among adults 18-34, the CW has also decreased by double-digit percentages.

Here are the final national results from Thursday, Oct. 30 through Wednesday, November 12 (with percent change versus the year-ago period in parentheses):

Total Viewers:

CBS: 11.33 million (- 8 percent), ABC: 10.86 (- 5), NBC: 8.11 (- 3), Fox: 6.72 (-17), CW: 2.22 (-24)

Adults 18-49:

ABC: 3.3 rating/9 share (-11), NBC: 3.0/ 8 (- 8), CBS: 3.0/ 8 (-14), Fox: 2.7/ 7 (-16), CW: 1.0/ 3 (-17)

Adults 25-54:

ABC: 4.0/11 (- 7), CBS: 3.9/ 9 (-11), NBC: 3.4/ 8 (- 3), Fox: 2.8/ 7 (-15), CW: 0.9/ 2 (-18)

Adults 18-34:

ABC and NBC: 2.8/ 8 (-10 each). Fox: 2.6/ 7 (-19), CBS: 1.6/ 6 (-21), CW: 1.3/ 4 (no change)