The sustained effect of the iPhone 4S is triggering a decline in Android's US market share, Nielsen showed Wednesday. Although Android had an average 51.7 percent share for the fall among recent buyers, a month-by-month breakdown by the researchers showed that OS share among recent buyers dropped from 61.6 percent in October to 48.7 percent in November as iPhone sales traffic picked up. By December, Android and iOS were near even, at 46.9 and 44.5 percent each.
