advisor vs coadjutor

advisor

noun
  • One who offers advice. 

  • A xiangqi piece, that is moved one point diagonally and confined within the palace. 

coadjutor

noun
  • An assistant or helper. 

  • An assistant to a bishop. 

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