Total global mobile-data traffic increased 69 percent in 2012, compared with 2011 figures, amounting to 13,412 petabytes. ABI Research finds 3G data usage accounted for 46 percent of the total, with an increase of 130 percent year over year. However, 4G LTE traffic is accelerating, with a growth rate of 207 percent predicted for this year, compared with 99 percent for 3G. Underpinning mobile-data usage are smartphone apps, their downloads, and the traffic usage they generate. By 2018, larger mobile-device screens and higher 4G data speeds will stimulate mobile video streaming/downloads to account for 56 percent of total traffic.