U.S. technology giant Apple Inc. said Tuesday that the online Apple Store reached $10 billion in application sales in 2013, including $1 billion in December. December, the company said, was the most successful month ever for its online retail business. In the final month of the year, consumers downloaded close to three billion apps, the company said. "With the introduction of the iOS 7, developers were able to create stunning apps that took advantage of the redesigned user interface and the more than 200 new features and APIs," Apple said in a statement. To date, developers who create applications for Apple products have earned $15 billion through Apple Store sales, Apple announced.