According to a new report from eMarketer estimating the media consumption of adults in the U.S., the average amount of time spent with digital media per day will surpass television viewing for the first time this year. This is due largely to the shift in smartphone and tablet usage now that most consumers lead increasingly mobile lives. Since 2010, mobile activity has grown from a mere 24 minutes per day on average to 2 hours and 21 minutes per day.

“The average adult will spend over 5 hours per day online, on nonvoice mobile activities or with other digital media this year, eMarketer estimates, compared to 4 hours and 31 minutes watching television. Daily TV time will actually be down slightly this year, while digital media consumption will be up 15.8 percent,” according to eMarketer.

Average mobile time currently involves 1 hour and 7 minutes per day on smartphones, and 1 hour and 3 minutes on tablets.

“What’s with the shift?” asks GigaOM. “Mobile, mostly. This is the first time eMarketer has included time spent with smartphones and tablets in its overall digital time figure. But either way, there has been more than a 30-minute increase in time spent with digital media each year since 2010, when the average amount of time spent online was 3 hours and 14 minutes.”

“eMarketer’s estimates of time spent with media include all time spent within each medium, regardless of multitasking. Consumers who spend an hour watching TV while multitasking on tablet devices, for example, would be counted as spending an hour with TV and an additional hour on mobile,” explains the report. “Such multitasking helps to contribute to the increase in the overall time people spend with media each day, which eMarketer expects to rise from 11 hours and 39 minutes in 2012 to 11 hours and 52 minutes this year.”