Apple just announced its year-end numbers for the App Store, and the totals are impressive. Customers spent more than $10 billion at the app store in 2013, and Apple says its developers have now earned more than $15 billion from the store. Thanks to the holiday rush, December was the best month on record for the App Store, with more than $1 billion in sales and nearly three billion total app downloads. Apples Eddy Cue, senior VP of internet software and services, applauded the milestone, crediting the success to both loyal customers and innovative developers in turn.