Mobile app downloads should grow 17 times larger in the next few years, IDC says in a new prediction (pay-only) on Tuesday. Apps for Android, iOS and other platforms is estimated to grow from 10.7 billion downloads for all of 2010 to 182.7 billion in 2015. Researchers aren't willing to predict which platform will lead that group, although iOS remains in front so far at 425,000 apps.