IDC reported that global tablet shipments hit 28.2 million units in the fourth quarter of 2011, up 56 percent compared to the previous quarter and 155 percent compared to the same quarter a year earlier. Tablet sales for 2011 as a whole grew more strongly than expected with a total of 68.7 million units shipped. Apple continued to dominate but Amazon shipped 4.7 million Kindle Fire devices, giving it a 16.8 percent market share. Despite shipping more units, book retailer Barnes & Noble secured a 3.5 percent market share, down from 4.5 percent. IDC is now forecasting that 2012 tablet sales will reach 106.1 million units, compared to its earlier forecast of 87.7 million units.