Mozilla Firefox reached its four millionth download last week, three years after it was first released.

The free Firefox web browser, which is distributed by Mozilla, has a 28-percent share of the European market, according to a report released in July by French web analytics company, XiTi Monitor.

Hungary has seen the most dramatic increase in Firefox use, from 27.2 percent in the March 2007 survey to nearly 40 percent in July. At a global level, Mozilla has around 15 percent of the market, with South America seeing the biggest increase.

In November 2004, a movement called Spread Firefox was started by supporters of the web browser. In just under 100 days, 25 million people downloaded the open-source browser. In less than six months, this figure rose to 50 million and within a year the 100 million download mark had been reached. Last year saw this number double to 200 million downloads.

Supporters of the Firefox web browser who helped spread the word were then thanked on the Spread Firefox site. "Thank you for helping Firefox to deliver on the great promises of the web. On behalf of the hundreds of millions of Firefox users, thank you for all that you have done in just three short years," the post read.

The report claims that 145 million people have downloaded Mozilla Firefox in the past year, which is a 56 percent increase on the previous year.