Smartphone shipments rose 55% Y-o-Y in Q4 2011

"The worldwide smartphone market grew 54.7% year over year in the fourth quarter of 2011 (4Q11), as Apple unleashed its iPhone 4S on an eager marketplace. According to the International Data Corporation (IDC) Worldwide Mobile Phone Tracker, vendors shipped 157.8 million units in 4Q11 compared to 102.0 million units in the fourth quarter of 2010. The 54.7% year-over-year growth was higher than IDC's forecast of 40.0% for the quarter, and higher than the 49.2% growth in 3Q11.
On a full-year basis, total smartphone shipment volumes reached 491.4 million units in 2011, up a strong 61.3% from the 304.7 million units in 2010. This was higher than IDC's full year estimate of 54.7% for the year, but still below 2010's year-over-year growth of 75.7%. Although this marks a slowdown from 2010, IDC still fully expects continued double-digit growth for the foreseeable future."

Source:  Data from IDC reported in a press release, 6th February 2012