Apple has announced that customers of its App Store spent more than $1 billion in December alone, and more than $10 billion across the whole of 2013. The company announced the mammoth figures today, noting that it means iOS developers have now earned more than $15 billion through the App Store. These figures were obviously given a bit of a boost approaching Christmas, as in December alone nearly 3 billion apps were downloaded from the App Store. Some of the surprise hits from across the year included Heads Up, Moves and Impossible Road, and then of course there were the runaway successes like Candy Crush Saga, Puzzles & Dragons, Minecraft and QuizUp. In total, there are more than one million apps available to download from the App Store. iPad-specific apps are now around the 500,000 mark, Apple said.