Apple’s use of Swift in iOS 13

Swift was introduced at Apple's 2014 WWDC and it is interesting to measure Apple's own use of Swift in iOS over the years. iOS 9 released in 2015 included a single application written with Swift: Calculator. Since then the number of applications using Swift in iOS has grown each year with iOS 10.1, iOS 11.1 and iOS 12.0. Now that iOS 13.1 is available, let's measure how many applications are using Swift this year. Apple is clearly increasing its usage of Swift, and dogfooding it properly around its mobile operating system. That should give developers confidence to use Swift themselves.