Mac OS X North American installed base almost 11%
Web analytics firm Quantcast has recently published some usage statistics for operating systems, broken out into geographical regions. The company's data shows that 10.9 percent of online users in North America are using Mac OS X, an increase of nearly 30 percent over the past year.
Unlike determining market share by units sold, Qauntcast measures OS share by comparing the operating system of users via the company's "audience measurement services," similar to statistics gathered by Net Applications. Such usage patterns can give us a rough idea of the installed base of an OS among end users.