Methodology: YoY % change in number of 30 second spots aired on top 25 TV networks based on ad revenue: CBS, NBC, ABC, FOX, ESPN, TNT, TBS, HGTV, FOOD, USA, BRAV, MTV, HALL, HIST, DISC, CNN, COM, ADSM, FNEW, E!, A&E, AMC, VH-1, TLC, TRU