not long for this world vs septuagenarian

not long for this world

adj
  • Unlikely to endure for much more time. 

septuagenarian

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

adj
  • Of or related to seventysomethings. 

How often have the words not long for this world and septuagenarian occurred in a corpus of books? (source: Google Ngram Viewer )