Just one month ago, Samsung announced that 10 million units of the Galaxy S 4 smartphone were sold within its first month of being launched. Now, 20 million units have been sold after just 68 days. This easily makes the GS4 the fastest-selling Android smartphone ever. In comparison, the iPhone 4S took 79 days to pass 32 million units shipped, while the iPhone 5 took 100 days to surpass 34 million units. At this pace, Samsung should fall short a bit, but ultimately, this shows that Android in general is making quite a comeback.