AT&T (NYSE:T) said it recorded more than 2.7 billion connections to its Wi-Fi network last year, according to a recent release. The carrier said the figure is more than double the number it recorded in 2011. Perhaps more importantly, AT&T also said it saw three times more mobile device traffic, over 5.2 billion MB, exchanged on its Wi-Fi network in 2012. The carrier said 40 percent more connections were made in the fourth quarter of 2012 from smartphone and tablet devices compared with the fourth quarter of 2011. AT&T's figures dovetail with recent numbers from Cisco--the vendor recently wrote that "the shift from cellular to Wi-Fi is occurring faster than we had anticipated." In other figures from AT&T, the carrier said it saw 17 percent growth in smartphone sales and 139 percent growth in tablet sales to business customers from the end of the fourth quarter of 2011 to the end of the fourth quarter of 2012. Release