IDC reports that Microsoft shipped 900,000 Surface tablets and that Windows 8 and Windows RT shipments totaled 1.8 million during the first quarter, making it the fifth biggest maker of tablet computers. Amazon was fourth with 1.8 million Kindle tablets shipped, Asus was at number 3 with 2.7 million tablets shipped (such as Google’s Nexus 7), Samsung landed at two with 8.8 million tablets shipped during Q1 and Apple lead the way with 19.5 million iPads shipped.

“Sustained demand for the iPad mini and increasingly strong commercial shipments led to a better-than expected first quarter for Apple,” Tom Mainelli, research director for IDC. “In addition, by moving the iPad launch to the fourth quarter of 2012, Apple seems to have avoided the typical first-quarter slowdown that traditionally occurred when consumers held off buying in January and February in anticipation of a new product launch in March.”

Overall tablet shipments grew 142.4 percent year over year to 49.2 million, better than the entire first half of 2012. While Apple was far and away the biggest maker of tablet computers and saw its shipments nearly double from last year, its market share was down from 58.1 percent last year to 39.6 percent.