Worldwide sales of Android-based smartphones are expected to grow 900 percent by year’s end, according to a report from research firm Strategy Analytics. Meanwhile, the Apple iPhone should continue to see strong sales but remain the second fastest-growing handheld platform. Research In Motion’s BlackBerry is not expected to lose its footing, standing firm as the second most popular smartphone operating system in the U.S. last year, according to the report. The Android OS is currently available in just one smartphone in the U.S.