ability vs functionality

ability

noun
  • The quality or state of being able; capacity to do or of doing something; having the necessary power. 

  • A unique power of the mind; a faculty. 

  • A skill or competence in doing; mental power; talent; aptitude. 

  • Physical power. 

  • The legal wherewithal to act. 

functionality

noun
  • The ability to do a task, performance, or execution; a set of functions that something is able or equipped to perform. 

  • The presence of a functional group. 

  • In United States trademark law, the tendency of a product design to serve a function other than identification of the product, preventing that design from being protected as a trademark. 

How often have the words ability and functionality occurred in a corpus of books? (source: Google Ngram Viewer )