roger vs trephine

roger

verb
  • To have sexual intercourse. 

  • Of a man, to have sexual intercourse with (someone), especially in a rough manner. 

  • To acknowledge by saying "roger". 

noun
  • An act of sexual intercourse. 

intj
  • Received (used in radio communications to acknowledge that a message has been received and understood) 

trephine

verb
  • To perforate with a trephine. 

  • To use a trephine during surgery. 

noun
  • A surgical instrument with a cylindrical blade used to remove a circular section of tissue, f.e. bone or cornea; a trepan. 

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