Editor’s note: This article originally appeared on Computerworld.com

Microsoft’s browsers hemorrhaged another 40 million users last month, according to analytics vendor Net Applications, pushing the year’s total number of deserters near the one third of a billion mark.

Net Applications pegged the combined user share of Internet Explorer (IE) and Edge at 28.4% for October, a fall of 2.3 percentage points. The month’s decline was the second-largest ever for Microsoft’s browsers, behind only May’s plummet of 2.7 points.

Unlike in most previous months, Microsoft’s bane was not Google’s boon, but instead Mozilla’s. Firefox’s user share jumped nearly 2 percentage points, to 11.1%. Atop an almost-as-large increase in September, Mozilla’s Firefox has stepped away from a precipice, and in two months recovered almost all the losses it incurred during the past year.

IE has shed 20.2 percentage points in 2016, and the fall shows no sign of stopping, or even slowing. In the last six months, four have recorded declines of 2 points or more, twice the number of the six months before that.

If declines continue at the rate of the last 12 months, IE + Edge will drop below the 25% mark in December, and under 20% by March, Computerworld calculated.

Although most Microsoft deserters have ended up on Google’s Chrome, the pace of the latter’s gains has slowed the last two months. Chrome added six-tenths of a percentage point to its share in October, just over a third of the average over the last 12 months. Chrome accounted for 55% of all browsers for October.

Firefox’s very large increases in September and again in October were puzzling. October’s was the largest single-month boost to Firefox’s user share in Computerworld’s tracking, which began in January 2005. One possible explanation: Net Applications’ measurement may represent a recalibration of Firefox’s performance, and thus a rejection of the steady decline it previously portrayed for the last year.

Using Net Applications’ data for browser and operating system user share, as well as Microsoft’s claim that about 1.5 billion PCs run Windows worldwide, Computerworld put the collapse of IE (and Edge’s inability to make up those losses) in terms of millions of users.

At the end of October, IE and Edge were being run by approximately 466 million users, down 40 million from September’s 506 million. Since January 1, 2016, IE and Edge have lost about 331 million users.

To put that in perspective, Net Applications’ data showed that Windows 10 powered approximately 371 million PCs in October.

Data: Net Applications More than 331 million users deserted Microsoft’s browsers this year, 40 million just last month. How low can IE (and Edge) go?

This story, "Another 40 million people bolt from Microsoft's browsers as mass exodus continues" was originally published by Computerworld .