http://windowsitpro.com/paul-thurrotts-wininfo/windows-8-makes-small-gains-microsoft-poised-announce-its-replacement?NL=News_WIN_WinInfoDaily_issue090814%20-%20Batch&E_ID=13433982&NLL=5231
quoted from the above referenced article:
Microsoft is expected to announce Windows 9 (codenamed Threshold) at the end of the September, putting an end to the most damaging setback in the history of its most lucrative product line. As things stand now, Windows 8 usage trails even that of Windows Vista during the same timeframe after its launch. And Vista was previously regarded as the firm's biggest flop.
According to NetApplications, Windows 8 (including all permutations of the OS, such as Windows 8.1) accounted for just 12.7 percent of PC usage worldwide in August, up slightly from 12.5 percent in July. That places Windows 8.x well below both Windows XP—with 24.8 percent usage—and Windows 7, which is holding steady at about 51 percent of usage. (Mac OS X falls in at about 6.7 percent, NetApplications reports, and Linux accounts for about 1.7 percent.)
By comparison, Windows Vista accounted for about 14.3 percent of all PC usage worldwide at this point after its launch. So use of Vista, long regarded as the biggest Windows flop, actually outpaced that of Windows 8.