According to IDC's Worldwide Quarterly Tablet Tracker, tablet shipments reached a record 52.5 million units worldwide in Q4 2012. Apple remains the leader in the tablet market with shipments of 22.9 million units and a 43.6 percent market share. This is a 48 percent year-over-year increase in tablet shipments.
Though Apple is shipping more tablets per quarter, its overall market share is declining slightly from 46.4 percent in Q3 2012 down to the current 43.6 percent. This decline can be attributed to competition from vendors like Samsung, which saw its tablet shipments grow to 7.9 million units last quarter (a whopping 263 percent year-over-year increase). Though their yearly increases were less than 10 percent, Amazon and Barnes & Noble also gained market share in the quarter.
Apple also faces competition from smaller tablets makers like Archos, Acer and others. Companies that sell less than 1 million tablets are grouped by IDC into the "Others" category and this conglomerate grabbed 22.1 percent of the market.