Though the iPad Mini launch helped Apple (NASDAQ:AAPL) sell 22.9M iPads in calendar Q4, the company's tablet shipment share fell 810 bps Y/Y to 43.6%, per IDC. Samsung (OTC:SSNLF), meanwhile, is estimated to have more than doubled its share to 15.1%. Amazon (NASDAQ:AMZN), believed to have shipped 6M Kindle Fires, is given an 11.5% share (-440 bps Y/Y). Nexus 7 maker Asus is at 5.8% (+380 bps), and Barnes & Noble (NYSE:BKS) at just 1.9% (-270 bps). IDC believes total shipments rose 75% Y/Y to 52.5M (equal to 58% of PC shipments), and is forecasting 172.4M for 2013. (previous)