Study: Time Spent on Mobile Devices Doubled in 2015Use of so-called phablets has also exploded, and may soon become the top type of mobile device.

If there's anything we learned in 2015, it's that we're obsessed with mobile devices.

Time spent on mobile devices was up 117 percent in the year compared to 2014, Flurry, a Yahoo-owned analytics company, said in areporton Tuesday. The data, which looks at worldwide smartphone and tablet use, found that usage among "phablet" owners, or those who have a large-screen smartphone, was up 334 percent year over year. In comparison, usage time was up 81 percent for small-screen slates and 26 percent for larger tablets.

By 2017, Flurry said that phablets will top smaller smartphones and be the most-used mobile device type.

Phablets are a category of smartphones with large screens (generally in excess of five inches). While the devices have been available for a few years, phablet usage started to explode in 2014 following to premiere of Apple's big-screen iPhone 6 Plus. Apple has since introduced an updated (and similarly popular) phablet in the iPhone 6s Plus. Meanwhile, competitors, including Samsung, LG, and others, have also found a welcoming marketplace for their own phablets.

Phablet popularity has translated to a significant growth rate in the way people access apps on those devices. For instance, Flurry found that between 2014 and 2015, use of news and magazine apps on phablets was up 721 percent year over year, compared to 135 percent across all mobile devices, including phablets. Use of sports apps was up 274 percent on phablets during the same period.

Flurry, which bases its information by tracking app usage on 2.1 billion smart devices around the world, found that total mobile device usage was up 58 percent in the last year. Although the rate was up, it was down from the 76 percent growth rate the mobile industry tallied in 2014.

The study did not disclose actual amount of time spent.

"While the growth rate has declined, it remains stunning as rates like these are rare in mature industries," Yahoo senior vice president of product and engineering Simon Khalaf said in a statement. "What was even more impressive is the majority of that growth rate came from existing users vs. new users. In fact, in 2015, we estimate that 40 percent of the 58 percent total growth in sessions came from existing users, compared to 20 percent in 2014 and 10 percent in 2013."

Despite all of the good news, there was one bit of bad news for the mobile industry in 2015: worldwide game playing fell 1 percent on mobile devices compared to 2014.

Even so, it's hard to find rough spots for the mobile industry in 2015. As Khalaf says, it's "showing a fast increase in mobile addicts."