long in the tooth vs octogenarian

long in the tooth

adj

  • Old; aged. 

octogenarian

adj

  • Of or related to eightysomethings. 

noun

  • Synonym of eightysomething: a person between 80 and 89 years old. 

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