With so many TV networks embracing the second screen to interact with viewers of their shows, the big question is, what exactly is the demo that turns to mobile devices while staring at the tube?Almost everyone: Overall, 84% of Americans use a mobile device while watching TV at least once a month, while 40% do so on a daily basis. More women: An estimated 40% of female viewers reach for their smartphones while in front of a TV, versus 35% of males. Boomers: Surprisingly, second screen use is higher among older auds, according to Nielsen’s Cross Platform Report, with 44% of 55-64-year-old TV viewers using tablets to enhance their viewing experience using apps and social media. Among 35-54-year-olds, it’s 36%. Devices dominate: Over 50% of Americans now own a smartphone, while one-fifth of U.S. homes now have a tablet.