The March launches of Internet Explorer 9 (IE9) and Firefox 4 failed to stop Microsoft's and Mozilla's decline in browser share, new Web usage data published Sunday showed.
According to California-based Net Applications, one of a handful of companies that regularly publishes browser usage data, IE lost eight-tenths of a percentage point of share in April, falling to 55.1%, a new low for Microsoft.
Meanwhile, Firefox dropped two-tenths of a percentage point to 21.6%, a share equivalent to its December 2008 standing.
Both Microsoft and Mozilla debuted new browsers several weeks ago: The former launched IE9 on March 14, while the latter shipped Firefox 4 on March 22. Neither release stemmed their maker's long-standing slide.
Apple's Safari and Google's Chrome took up the slack in April.
Safari posted an increase of five-tenths of a point to end the month at 7.2%, a record for the browser that ships with Mac OS X, and is integrated with iOS, the mobile operating system that powers the iPhone and iPad. The one-month gain was Safari's biggest-ever by Net Applications' tracking.
Chrome's usage share grew by four-tenths of a percentage point, slightly less than the browser's average increase over the past 12 months. Google's browser accounted for 11.9% of all browsers used in April.
Opera, the Norwegian browser that rounds out the top five, was flat last month at 2.1%.
Data from Irish analytics company StatCounter differed from Net Applications' in share amounts for each browser, but showed the same trends: IE and Firefox losing share, Safari and Chrome gaining.
But while Net Applications had IE and Firefox down overall, the newest versions attracted existing users.
IE9 accounted for 2.4% of all browsers, a 1.4-point increase, nearly three times March's gain. The surge was likely fueled by the IE9 upgrade offer that Windows 7 and Vista users started see via Windows Update on April 18.
But highlighting Microsoft's difficulty recouping lost share, IE9's growth was almost exactly offset by a 1.4-point drop in the older IE8, the browser that shipped with Windows 7 and which most Vista users have been running since mid-2009.
All of Microsoft's older browsers continued their steady fall. IE6, the browser Microsoft has campaigned to kill, fell by one-tenth of a point to 10.9%, while IE7 slipped by five-tenths of a percentage point to 7.4%. And IE8 dropped for the second consecutive month to end April at 33.1%, a number about equal to its July 2010 share.