elderly vs long in the tooth

elderly

adj
  • old; having lived for relatively many years. 

  • Of an object, being old-fashioned or frail due to aging. 

noun
  • An elderly person. 

  • Older people as a whole. 

long in the tooth

adj
  • Old; aged. 

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