Last month, Windows 8 hit a milestone in having its market share surpass every version of Mac OS X combined. According to Net Applications, this month Windows 8 has passed eight percent market share, with Windows 7 also seeing significant gains.

The gains to both Windows 7 and Windows 8 have come at the expense of Windows Vista, but more so to Windows XP, which lost a huge 2.25% of the market between August and September. Going on current trends it's likely Windows XP will drop below 30% next month, which will be for the first time in many years.

Net Applications: Operating system market share, September 2013

Operating System September 2013 Market Share August 2013 Market Share Market Share Gain
Windows 8 8.02% 7.41% 0.61%
Windows 7 46.43% 45.63% 0.80%
Windows Vista 3.98% 4.11% -0.13%
Windows XP 31.41% 33.66% -2.25%
Windows Other 0.99% 0.38% 0.61%
Windows Total 90.83% 91.19% -0.36%
Mac OS X 7.53% 7.28% 0.25%
Linux 1.64% 1.52% 0.12%

Overall, Windows' market share decreased slightly in September, which saw both Mac OS X and Linux gain a small percentage of the market.

Windows 8 market share is only going to grow, with the official release of Windows 8.1 coming later this month. Windows 8.1 will not only usher in a new range of Windows-based devices, but it will address a range of complaints that users had in regards to Windows 8. The free update will be available through the Windows Store on October 18th, the same day full retail SKUs will appear in stores.