centenarian vs emeritus

centenarian

noun
  • One who or that which is at least 100 years old. 

adj
  • Aged 100 years or more; extremely old. 

  • Of or relating to centenarians or a centenary celebration. 

emeritus

noun
  • A person retired in this sense. 

adj
  • Retired, but retaining an honorific version of a previous title. 

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