convenience vs flexibility

convenience

noun
  • The quality of being convenient. 

  • Any object that makes life more convenient; a helpful item. 

  • A convenient time. 

verb
  • To make convenient 

flexibility

noun
  • The quality of being flexible; suppleness; pliability. 

  • The quality of having options. 

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