not as young as one was vs septuagenarian

not as young as one was

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 as young as one was and septuagenarian occurred in a corpus of books? (source: Google Ngram Viewer )