During his keynote presentation to developers attending this week’s Worldwide Developers Conference (WWDC), Apple CEO Steve Jobs revealed that the App Store has paid out more than $1 billion to developers since going online. Apple returns 70 cents of every dollar spent on apps to developers.

Jobs noted that as of Monday, the App Store is home to more than 225,000 applications for iPhone, iPod touch and iPad. “There’s nowhere else you can go and find over 225,000 apps,” said Jobs.

The iPad, released in early April, now touts 8,500 native applications, according to Jobs. More than 35 million iPad app downloads have taken place so far — that works out to be about 17 apps per iPad.

Jobs also tackled iPhone app approval – an issue that’s gotten coverage on many technology Web sites and blogs in the past few months. Jobs said that 95 percent of all apps submitted to the App Store for approval are approved within one week. Apple receives about 15,000 apps every week that need approval, including updates – that figures to about 14,250 passing the approval process.

Jobs claims that there are three top reasons why the remaining 5 percent don’t make it: The app doesn’t function as advertised by developers; the app uses private Application Programming Interfaces (APIs); and the apps crash.

“I think if you were in our shoes you would reject these apps,” Jobs said.