Worldwide market share for tablet systems

Apple’s iPad and the iOS system running it dominate the market for tablet computers despite growing competition, according to Gartner. On Thursday, Inc. is expected to unveil a successor to its Kindle Fire tablet computer.

Here are Gartner’s figures for worldwide unit sales and market share for tablet computers in 2011 and projections for 2012.

The figures are broken down by operating system. Android includes modified versions used in Inc.’s Kindle Fire and Barnes & Noble Inc.’s Nook Tablet. Tablets based on Windows will come out later this year with the Oct. 26 release of Windows 8. The report came out before Research in Motion Ltd. announced yet-another delay in its new BlackBerry 10 operating system, which could affect sales for 2012.

iOS (Apple Inc.’s iPad) ? 40 million units, 66.6 percent share in 2011; projected 73 million units, 61.4 percent share in 2012

Android (Google Inc.) ? 17.3 million units, 28.8 percent share in 2011; projected 37.9 million units, 31.9 percent share in 2012

Windows (Microsoft Corp.) ? none in 2011; projected 4.9 million units, 4.1 percent share in 2012.

QNX/BlackBerry (Research in Motion Ltd.) ? 807,000 units, 1.3 percent share in 2011; projected 2.6 million units, 2.2 percent share in 2012.

Other ? 1.9 million units, 3.2 percent share in 2011; projected 510,000 units, 0.4 percent share in 2012.

Source: Gartner Inc.