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Most reports of holiday shopping behavior showed that U.S. consumers went mobile in a big way this year. The fact is, U.S. computing is going more mobile all the time.

A report posted Tuesday by Flurry, a division of Yahoo Inc. (NASDAQ: YHOO), noted the mobile app usage grew by 58% year over year in 2015. That is, believe it or not, down from growth of 76% in 2014 and 103% in 2013. The impressive thing, however, is that Flurry estimates that 40 points of that growth came from existing users, double the 2014 total and four times the 2013 total. In other words, once consumers get their hands on mobile apps, they use the apps more and more.

What are the most popular categories of apps? Personalization (think emojis), news and magazine apps, utilities and productivity apps, and lifestyle and shopping apps. Growth among personalization apps reached 332% in 2015, while news/magazine app growth reached 135%, productivity app growth rose 125% and lifestyle/shopping app growth rose 81%. Of the 10 categories Flurry tracks, only games saw a decline in growth, and that just a meager 1%.

Another unexpected discovery was the popularity of apps on phablets, those giant phones with big screens. Consumers spent 334% more time on phablets in 2015 than they did in 2014. Flurry reasons “that the extra inch of real estate has made the phablet the ultimate media consumption device.” New/magazine app usage on phablets grew at 4.8 times the growth rate of all devices, while sports app usage grew at 4.6 times the growth rate of all devices and music/media/entertainment app usage grew at 4.0 times the rate for all devices.

Flurry also noted the 27% of all new device activations for Christmas in 2015 were phablets, and 50% of all Android devices activated were phablets. Flurry’s analysis also indicated that if the growth rate of phablet usage continues, by October of 2016 the phablet will become the dominant form factor among mobile devices.