For professional iOS developers, Swift is more commonly used than Objective-C according to Stack Overflow's 2018 Developer Survey. Released in 2014, Swift is a general-purpose, multi-paradigm, compiled programming language, developed by Apple, for use in iOS, macOS, and Linux. Swift is designed to work with Apple’s Cocoa framework, as well as Objective-C code, and supports dynamic dispatch, widespread late binding, extensible programming, and protocol extensibility. In 2017, Swift ranked 11th on TIOBE’s index ranking of popular programming languages. The demand for iOS developers is higher than for Android developers, and so is their average hourly rate — iOS developers charge approximately $81-100/hr worldwide.