Although cable networks are slowly trimming the number of commercials in their programs, those networks on average still air more advertising messaging than broadcast TV networks -- by over a minute and 23 seconds per hour. Nielsen says commercial clutter on cable networks averaged 15 minutes and 38 seconds for each hour of network TV programming in 2013 -- down 2 seconds from its level of 15:40 in 2012. Broadcast networks, meanwhile, grew 10 seconds per hour to 14:15 from 14:05 in 2012. Overall, both cable and broadcast networks have increased their respective commercial content per hour of programming since 2009 -- broadcast at 13:25 and cable at 14:27 that year. Nielsen says the average prime-time TV spot in broadcast was $75,000 in 2013, with the average national cable network commercial at $7,800. Total TV ad spending climbed 3% to $78 billion in 2013 -- down from the gain in 2012 when it rose 6% to $76 billion. In 2013, Nielsen says 53% of the 14,466 TV commercials had a duration of 30 seconds -- down from 56% the year before. Last year, 44% of commercials were 15 seconds long -- up from 40% in the years from 2010 through 2012. Two percent of the commercials were 60 seconds in length, virtually the same in recent years.