The Smartphone is Eating the TV, Nielsen Says 

A new study of media and attention by Nielsen Co. confirms what has now become conventional wisdom: Smartphones are winning and traditional television is losing, especially when it comes to viewers in the most desirable 18 to 34 demographic. Nielsen also says that traditional TV viewing by all age groups peaked in the 2009-2010 season, and has been on the decline ever since. Until that point, the audience for TV had grown every year since 1949.

Source: The Smartphone is Eating the TV, Nielsen Says – Fortune