Windows 7's one year anniversary is rapidly approaching, and despite being hailed as the quickest selling operating system, Windows XP remains number one in global usage. According to stats provided by Net Applications, XP holds 60.03% of the market, down slightly from last month's 60.89% and last year's 70.48%. Naturally, those numbers factor in rival platforms, but XP currently represents 66% of all Windows machines.

Vista's overall share slipped from 14% to 13.35% during the recent sequential period, which equates to 14.66% among Windows users – much lower than its all-time high of 20.35%. Windows 7 gained about 1.25% on-month, moving from 15.85% to 17.10%, or 19% of all Windows systems. Microsoft's OS share as a whole has fallen by nearly 1% over the last nine months, but it's not clear what platform has benefited from Redmond's loss.

StatCounter, another research firm, puts XP at 53.99%, Vista at 16.59%, and Windows 7 supposedly holds 22.04% of the total market. That breaks down to 58%, 18%, and 24% of all Windows computers. ConveivablyTech notes that while the numbers may be different between outfits, the overall trend is similar: Windows 7 is chipping away at XP and Vista.