Still, that figure is dwarfed by the average time Americans spent watching traditional TV, at 142:38 per month, down slightly from 146:37 a year ago.
Mobile also lags the desktop Internet as a video platform, where people spent 10:35 watching video, up from 6:28 a year ago. However, the mobile video audience is catching up to the 145.5 million on the Web, which is down from 150 million a year ago.
As you would expect, younger users are more likely to tune into TV shows or other programming on their phones than older ones. People in the 18-24 age group, for example, watched mobile video for an average of 2:48 monthly in the second quarter, compared to 1:56 for those ages 25-34, and just over an hour for people 50-64.
But the increase in time spent viewing mobile video cuts across age groups. When it comes to broader mobile media consumption— encompassing app and mobile Web use — Nielsen showed that the smartphone audience in the second quarter reached 157 million, up from 132.2 million a year ago. The corresponding time spent was 43:31 per month, up from 32:48.
During a typical day, a U.S. adult typically watches 4:36 of traditional TV, 2:45 listening to AM/FM radio, more than two hours (1:25) on their smartphone, 1:07 using the desktop Web, 31 minutes watching time-shifted TV and a total of about 20 minutes playing a console game or using a DVD/Blu-ray device.
Smartphone penetration overall has reached 72%, while 39% own tablets. However, a revised forecast released last week by research firm IDC projects flat growth for tablets in North America this year after a 25% gain in 2013. Waning demand for tablets is attributed primarily to the rise of large-screen smartphones, or phablets, which are on pace to out-ship tablets next year.