The other popular browsers globally, according to OneStat.com, are Apple Computer Inc.'s Safari, with 1.84 percent usage; Opera, with 1 percent usage; and Netscape, with 0.16 percent usage.

In the U.S., the most popular browsers are IE, which is used by 79.78 percent of surfers; Firefox, which is used by 15.82 percent; Safari, which is used by 3.28 percent; Opera, which is used by 0.81 percent; and Netscape, which is used by 0.2 percent of Web surfers.

Usage rates for IE and Firefox in Canada and the U.K. are similar to the U.S. statistics. But in Australia, Firefox is much more popular and is used by 24.23 percent of Web surfers. Microsoft's IE is used by 69.35 percent of Australian surfers, according to the study. In Germany, Firefox is even more popular: 39.02 percent of surfers there use it, compared with 55.99 percent who use IE.

Dana Gardner, an analyst at Interarbor Solutions LLC in Gilford, N.H., said the growing use of Firefox arises from several factors, including better performance and fewer security problems than IE.

"I think it's been an astonishing ramp-up that Mozilla's had," Gardner said. "And of course, there's been a long period of time [since the original release of] IE 6. We've only got the beta version of IE7, so Microsoft gave people an opportunity to check out other browsers" by not regularly updating its own, he said.