Sophos looked at 100,000 Mac computers and found that one in every five has some form of malware. This might sound alarming, but before you stare at your machine in disgust, you should get some perspective.
The survey looked at 100,000 OS X machines that are running Sophos's free Mac anti-virus software. Sophos found that this 20 percent figure is for malware that targets Windows-based computers. Though it can be used as a vector to infect other Windows machines, it won't affect Mac users on OS X.
Sophos did find that 1 in 36 Macs (2.7 percent) were infected with OS X malware. Though less than 3 percent may be concerning, it's not as alarming as the 20 percent figure that's making its way into headlines.