AT&T’s wireless revenues for the fourth quarter rose 4.8 percent annually in large part due to a 16.8 percent increase in wireless data revenue.

Wireless revenue hit $18.4 billion for the quarter and $5.7 billion of that came from data revenue. AT&T noted that data usage per smartphone increased 50 percent annually on its network.

That boost likely came from the 1.2 million smartphones added during the fourth quarter, a number that added to the 5 million total additions to the carrier’s smartphone base in 2013.

While the revenue from mobile data rose, AT&T’s net postpaid adds, totaling 566,000 for the quarter, fell short of rivals Verizon (1.6 million) and T-Mobile (870,000). One of the surprising net postpaid growth drivers for AT&T was tablets, with the carrier reporting 440,000 branded net tablet adds for the quarter.

After reporting a record 89 percent of postpaid phone sales attributed to smartphones, AT&T broke the record this quarter by reporting 93 percent.

The uptick in smartphone sale saturation could be coming from AT&T’s Next early upgrade plan. Introduced this year, Next has seen 1.5 million AT&T customers jump onboard. 

AT&T saw a record-low fourth-quarter churn of 1.11 percent but there was question if that could be sustained as competition for each other’s subscribers heats up between carriers.

In an earnings call broadcast  online, CFO John Stephens didn’t seem worried about the impact of programs like T-Mobile’s ETF payoff program.

AT&T’s stock was down more than one percent in after-hours trading.