During its WWDC event today, Apple says that it has a current Mac userbase of 66M, with 40% of those users on OS X Lion. To date, it has shipped 26M copies of the OS. Windows 7 took over two years to hit those kinds of numbers.

The 66M users overall is 3x what the company touted 5 years ago, showing that the company is making its way to more mainstream users with its line of desktop and laptop machines. It’s safe to say that those numbers will surely grow with the announcement of the new MacBook Air and Pro models.

Mountain Lion is going to be absolutely huge for Apple. If you’ve been waiting to upgrade, this will be the time.

This is a developing story, please refresh for updates.