Amazon has published some stats on the growth of its Amazon Appstore for Android to celebrate its first anniversary. The store now has more than 31k apps available, up from 4k at launch a year ago. Amazon hasn’t given an exact downloads number for the store, other than saying “millions of apps and games” have been downloaded from it. The most popular paid apps have been games: the top three is Cut the Rope, Angry Birds and Where’s My Water. In the free chart, the lite version of Angry Birds is followed by Netflix and Solitaire, although Amazon says Pandora has also been very popular with its customers. The store started life as an alternative to Google’s Android Market for smartphones, but it’s also now the downloads hub for Amazon’s Kindle Fire tablet.