Back in early 2009, Android was the epitome of a nobody. Apple was sitting prettily on top of the industry with barely any competition. Today, however, Android’s got everything in line, and it stands as the fiercest rival to iOS. We can’t help but wonder how a nobody rose to the number one spot in barely three years. With persistent effort maybe, added with sprinkles of prayer and good luck?

Aside from number of devices activated and ad network impressions, Android app downloads also surpasses that of the iOS, says ABI research.  Android accounts for 44 percent of apps downloaded, while it’s only 31 percent for iOS. This is credited to the growing device shipment of Android smartphones, increasing by 20 percent and 30 percent for this year’s first and second quarters respectively.  Apple, on the other hand, is experiencing a decline of 15 percent and 9 percent over the same period.  All the more, Android outnumbers iOS in global install base by a ratio of 2.4:1, and it’s expected to increase to 3:1 by 2016.

“Being a free platform has expanded the Android device install base, which in turn has driven growth in the number of third-party multi-platform and mobile operator app stores. These conditions alone explain why Android is the new leader in the mobile application market.”

Still, Apple users prove themselves to be hardcore user base, as they lead the number of downloaded apps per user. “Despite leading in total mobile application downloads, Android’s app downloads per user still lag behind Apple’s by 2-to-1,” says Dan Shey, practice director, mobile services at ABI.

The app install base in its entirety is expected to bloat to 29 billion by the end of 2011, compared to 2010’s 9 billion, due to the explosion of smartphones.

Below is an infographic bearing the figures that show Android as the top operating system in terms of population and number of apps downloaded. It also details the tight competition with the iOS, and it’s future behind hidden walls as it acquires Motorola and the potential threat borne within Windows Phone.

In previous reports, Android also demonstrates growing dominance, and along with it is the evident, gradual shifting of the smartphone popularity landscape.  It is safe to assume that this is partly brought about by the Samsung Galaxy Nexus, and the release of Android 4.0, Ice Cream Sandwich.