According to the web metrics firm, IE's total share fell to 57.1 percent, another record low for the Microsoft-made browser. IE has lost 5.6 percentage points in the last 12 months, and 10.7 points since IE8 was introduced in March 2009.
Meanwhile, Chrome and Apple's Safari again made the sharpest gains, boosting their shares to 10 percent and 5.9 percent, respectively, both records.
IE typically loses a greater-than-average share in December, with the fall credited by most experts to an increase in browsing time at home during the holidays. Home computers are thought to have a higher percentage of non-Microsoft browsers than work systems, where IE dominates.
But rather than dwell on IE's overall decline, Microsoft touted the increase of IE8's share at the expense of the older IE6 and IE7, a claim it's made before.
In the past year, the combined share of IE6 and IE7 has fallen by about 40 percent, shedding almost 16 percentage points, said Roger Capriotti, IE's director of marketing, in a January 1 blog. At the same time, IE8 and IE9 - the latter remains in beta, with a final release slated for the first quarter of this year - posted a gain of nearly 10 points.
Capriotti also said that IE9's preview has been downloaded about 20 million times since its mid-September 2010 introduction. In December, IE9 accounted for about half a percentage point of the global usage share, a slight increase from the month before and nearly equal to IE8's share five months before that browser's launch.
Recent chatter on the web has pegged January 28 as the likely launch date for IE9's release candidate, or RC, the final build before the company greenlights the browser.
Although both IE6 and IE7 lost ground last month - Microsoft has been especially aggressive in pushing customers to ditch the nine-and-a-half-year-old IE6 - the oldest browser returned to its usual decline of almost seven-tenths of a percentage point in December, about half the drop of the month before.
Capriotti did not speculate on why IE6's slide slowed last month.
If IE6 continues to lose share at the pace it's set over the last three months, it will drop under the 10 percent mark sometime in April. Microsoft has promised to support the aged browser until 2014.
Firefox and Opera Software's Opera both gained small amounts of share last month to finish the year at 22.8 percent and 2.2 percent, respectively. Firefox lost 1.8 points during 2010, while Opera slipped by two-tenths of a point in the same period.
Meanwhile, Chrome's share grew by seven-tenths of a point in December, more than doubling its share during the year to reach 10 percent for the first time. In 2009, Chrome's chief engineer set goals for the browser of 5 percent by September 2010 and 10 percent for September 2011, both which it easily met. Unless Chrome stalls, Google 's browser should own a 1 percent% share by September.
Net Applications calculates usage share from data acquired from the 160 million unique visitors who browse the 40,000 websites it monitors for clients. The company's December browser data is available on its site.
See also: IE9 to let users block tracking