Windows 7 is Microsoft's fastest selling operating system to date. It is now one and a half years old, yet it reached several key milestones quickly. Last August, its marketshare surpassed that of its older brother Windows Vista, and this past December its marketshare was sitting at 25%, while its decade-old elderly sibling Windows XP plummeted to 50%. Starting from this month, it finally managed to surpass Windows XP - it now sits at 31.8% while Windows XP is at 31.55%. The catch? This milestone is just for computers in the United States. However, the growth rates of Windows 7's marketshare and the decline of Microsoft's decade-old operating system remain constant globally and within the United States. Also, in other countries, this milestone has been reached already. This month's statistics from Statcounter.com shows Windows 7 at 31.8%, Windows XP at 31.55%, Windows Vista at 19.12%, Mac OS X at 14.74%, and Linux at 0.7%. The three versions of Windows command a marketshare of 82.47% in the United States. Marketshare across all Windows versions was down by a hairline, where Windows was on 82.58% of all American computers in December 2010. Windows 7's marketshare appears to be gaining entirely at the expense of both Windows XP and Vista combined, rising by 5.47% since December while XP and Vista fell by 2.54% and 3.04% respectively, or 5.58% combined. Windows XP still holds the top spot globally, at 47.1% compared to Windows 7's 31.28%. However, Windows XP's marketshare is falling faster globally than in the United States, dropping by 3.49% while Windows 7 rose by 5.42%. Global Windows marketshare also fell a slight amount to 91.64%, a 0.3% drop from December 2010. Windows 7 continues to ride with great momentum amongst the public, with Microsoft reporting 300 million Windows 7 licenses sold in January's second quarter earnings report, and the release of Service Pack 1 in mid February. Windows 7 also continues to have a presence in television commercials. Could Windows 7 take XP's strong majority spot by the time XP's extended support lifecycle ends in April 2014? Only time will tell.