At today’s “Let’s Talk iPhone” event, Apple CEO Tim Cook gave an update on Mac OS X 10.7 (“Lion”). He says that over six million copies of Lion have been downloaded; that’s 80% more than Mac OS X 10.6 (“Snow Leopard”).

Cook says it took Windows 7 about 20 weeks to reach 10% of their installed base, while Lion did it in two weeks. He also pointed out that in year-over-year growth for the personal computer industry, the Mac outgrew the PC market by almost six times. (23% to 4%). In fact, the Mac has outpaced overall PC sales every single quarter for the past five years and now has 58 million users.

“Still 77% of people own a computer that’s not a Mac,” Cook says. “That’s an incredibly high ceiling, so we still have a lot of room for growth.”