Europe is a fortress for Mozilla's Firefox browser, which enjoys a market share nearly 50 per cent higher than in the US, a French web-measuring company reported Monday.

According to July data from XiTiMonitor, Firefox accounted for 27.8 per cent of browsers used in Europe, an increase of 3.6 percentage points from the March measurement.

XiTiMonitor's survey of almost 96,000 sites in 32 European countries - from Ireland to Ukraine, Finland to Greece - also said Microsoft's Internet Explorer held a 66.5 per cent market share, with Opera, Safari and Netscape rounding out the top five with 3.5 per cent, 1.7 per cent and 0.3 per cent, respectively.

Slovenia, Finland and Slovakia had the greatest Firefox penetration, with the open-source browser accounting for 47.9 per cent, 45.4 per cent and 40.4 per cent, respectively, during a weeklong stretch from 2 July to 8 July. Other Firefox strongholds include Germany (38 per cent), Poland (39.6 per cent) and Ireland (38.6 per cent).

By XiTiMonitor's tally, Firefox's North American market share was pegged at 18.7 per cent, higher even than the worldwide number set by US-based metric vendors. Net Applications, for instance, put Firefox's June global market share at 14.55 per cent, which was off more than half a percentage point from March. XiTiMonitor, meanwhile, claimed that Firefox's share had climbed in every region.

SpreadFirefox, Mozilla's community marketing program, wasted no time in posting XiTiMonitor's numbers.