The Apple App Store, unsurprisingly and without much fanfare, passed the 150,000 application milestone this week. The world’s largest mobile application store, which contains over 27,000 books and over 28,000 games, has generated well over 3 billion downloads since its inception in July of 2008. Back in December 2008, when O’Reilly examined the App Store landscape, they calculated that 22% of the then 10,000 applications were provided free by developers. Today, according to analytics company Distimo, the App Store’s 150,000 app catalog has a ratio of 75% paid applications to 25% free applications; compare that with the second largest app store, Android Market, which has a ratio of 60% paid to 40% free. At the January 27th iPad announcement, Steve Jobs told the media that the App Store contained around 140,000 applications; Apple approved around 10,000 additional applications in the 16 days after that announcement.