septuagenarian vs superannuated

septuagenarian

adj
  • Of or related to seventysomethings. 

noun
  • Synonym of seventysomething: a person between 70 and 79 years old. 

superannuated

adj
  • Obsolete, antiquated. 

  • Retired or discarded due to age. 

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