Cable television viewing has continued to cut into the ratings for the broadcast networks this season and now accounts for 60.6 percent of the audience, according to the latest data from Turner Research and Nielsen Media Research published on Wednesday by MediaPost.com. A year ago the figure stood at 59.2 percent. Most of the growth has come during the 10 00 p.m. hour and is attributed to the exodus of viewers from NBC, which now airs the low-rated Jay Leno Show in that hour. However, not all cable networks have shared equally in the migrating audience, MediaPost noted, citing figures from CBS Vision's David Poltrack, who told the UBS Media Conference in New York on Wednesday that of 38 top ad-supported cable networks, seven grew from the previous year, while 12 declined and 19 went unchanged. Meanwhile, Nielsen released a new study today (Thursday) indicating that while total U.S. ad spending was down 11.5 percent during the first three quarters of 2009 versus last year, ad spending on cable TV was actually up 9 percent during the period and ad spending on Spanish-language cable TV was up a whopping 36.7 percent. Spending on network TV, by contrast, was down 13.9 percent, and on local TV stations it was down 21.4 percent.