• by Mark Walsh  @markfwal, May 7, 2014

Since April 2013, the number of mobile-only users has grown 36% to 19 million, while the total of PC users has tumbled 45% to 40 million. The overall number of mobile users is close to catching up with that on the PC side, at 163 million to 181 million. (The mobile total includes 128 million smartphone and 35 million tablet users.)

comScore last year noted that time spent on mobile devices for the first time surpassed that spent on PCs. For all of 2013, smartphone use totaled 472 minutes, tablets, 134 billion, and computers, 470 billion. What's most interesting for media and marketing types is how time spent breaks out by content vertical.

People spend 50% or more of their digital time on mobile devices in six of 14 categories examined: games, social media, streaming radio, retail, weather and health. Retail, where 53% of time is spent on smartphones and tablets crossed over to majority mobile this year. Health hit 50% exactly, while news (45%) and sports (44%) are poised for a similar move.

Automotive is still firmly entrenched on the desktop, where 76% of time spent takes place as people still overwhelmingly prefer to research car purchases on PCs. The same goes for travel, where 68% of time is spent on the desktop as people research trips. Business and finance, B2B and TV viewing are other categories that are skewing toward the desktop.

Looking at demographics, the study showed the biggest increase in cross-screen use was among people 50 and over, up 17% to 62% in the last year. That's much higher than those 18-24 -- where only 41% are cross-screen -- mainly because a larger chunk (21% versus 2%) are mobile only.

Time spent on smartphones for those ages 18-24 was up 20% to 54% -- the same proportion as for women 25-49. Men in that age bracket spent 41% of digital time on smartphones, while that figure fell to 29% for those 50 and over.

The report also provides some examples of how audiences break out for different categories. In retail, for instance, women 25-49 and adults 18-24 spend more than half their time on mobile devices, while games and streaming radio showed a mobile majority across all demographics.

The findings overall were based on analysis of data from comScore’s Multi-Platform measurement service and thousands of ad campaigns on Millennial Media’s mobile ad network.