In terms of content volume, Google Play is the largest app store. The number of apps available on Google Play has been constantly increasing since the release of the platform in 2008, jumping from 16 thousand in the end of 2009 to one million apps available in mid-2013. In 2019, there were 2.7 million apps available on the store. About 96 percent of the apps available on Google Play Store are free. Nonetheless, Google's digital content and app platform generates billion of dollars in revenue each year from sales of apps and games.
Apple's App Store is the second largest app store. As of the second quarter of 2019, the store had 1.96 million mobile apps available for download, up from 800 thousand in January 2013. Games are by far the most popular category on Apple's App Store, accounting for about a quarter of all apps available on the platform. Business, education, lifestyle and entertainment are also popular categories in terms of availability of apps.
The third-largest app distribution platform is the Amazon Appstore. The number of available apps in the Amazon Appstore increased from just fewer than four thousand in March 2011 to 478,990 in the second quarter of 2019. The Amazon Appstore does not only offer Android apps but also apps specifically optimized for its range of Kindle Fire tablets as well as the Fire TV and Fire Phone.