Some 52.5 million tablets shipped during the final quarter of 2012, and 22.9 million bore the Apple logo, according to the latest IDC data. However, rival Samsung managed to put a small dent in Apple's overall market share lead by shipping 7.9 million tablets, a year-over-year increase of 263 percent. Conspicuous by its absence among the top five tablet makers is Microsoft, which, according to IDC, shipped just 900,000 Surface tablets during the final quarter of 2012.