Apple patted itself on the back at the onset of its Worldwide Developers Conference (WWDC), flaunting growth figures alongside the competition's. The results, in case you didn't already guess, is the Cupertino, Calif. tech giant is doing pretty well.

The App Store, which has become a steady revenue generator for Apple, now has over 400 million accounts, according to CEO Tim Cook.

The size and momentum are just phenomenal, he said during his keynote at the event. This is the store with the largest number of accounts with credit cards anywhere on the internet that we're aware of.

The app store boasts 650,000 apps, 225,000 of which are iPad specific, with users crossing the 30 billion download threshold. That accounts for $5 billion in revenue from a total of 155 countries worldwide.

It's becoming an economy in and of itself, Cook said.

The company has also seen a user adoption rate of its latest operating system, OS X Lion, eclipse all previous releases. There are 66 million Mac users out there, and 26 million have bought copies of Lion since its release 10 months ago.

Cook called it Apple's best-selling release ever, comparing it to Windows 7's slow sales, which took 27 months to reach similar sales figures.

Apple's stock (NASDAQ: AAPL) decreased by 65 cents moments after keynote ended.