According to data from Valve's Steam Hardware and Software Survey for the month of December 2013, Microsoft's latest operating system usage has increased to a combined total of 20.06% for both Windows 8 and Windows 8.1. During the previous month, the usage was at a total of 18.45%. This factors in both 32bit and 64bit of Windows 8 and Windows 8.1.
For those that don't know, this data is collected by Valve's Steam game client and measures hardware and software stats on a monthly basis. According to this data, Windows 8 32bit has a share of 0.57%, which is a 0.05% drop compared to the previous month. Windows 8 64bit had a share of 10.65%, which was down by 0.84% compared to the previous month.
On the other hand, Windows 8.1 32bit went up to 0.30% in share, which was an increase of 0.07%. Windows 8.1 64bit saw an increase to 8.54%, up by 2.43% compared to the previous month. Windows 7, continued its drop in share with the 64bit version holding a 50.62% share while the 32bit version held a 12.34% share.
NetApplications also released their market share data earlier today, which revealed a combined Windows 8 and 8.1 operating system market share of 10.15%.