Today, iOS ranks as the second largest smartphone platform in the U.S. after Android, commanding 31.9 percent share of the market with its 35.1 million iPhone owners in May. During the last five years, Apple has introduced five different versions of the iPhone and extended its reach beyond AT&T to other major carriers, including Verizon and Sprint. A more detailed look at the iPhone ecosystem by device generation found that nearly 3 in every 4 iPhone owners currently uses the iPhone 4 or iPhone 4S, with the iPhone 4 accounting for the largest overall share at nearly 40 percent of iOS smartphones in May 2012. The original iPhone released on June 29, 2007 now accounts for just 2 percent of current iOS smartphone owners, with new generations of the device making the original virtually obsolete.