According to the latest data from research firm Gartner, Apple accounted for 17% of worldwide smartphone sales in the third quarter. Apple’s market share trailed only that of BlackBerry maker RIM, with nearly 21%, and Nokia, with 39.3%—an all-time low for the Finnish company. Apple’s 17% share is a substantial improvement over the year-ago quarter, in which it accounted for only 12.9%. In addition, Gartner says that iPhone sales…