cobber vs old fellow

cobber

noun
  • A pal, buddy, mate, friend; often used in direct address by one male to another. 

  • A sweet consisting of a small block of hard caramel covered in chocolate. 

old fellow

noun
  • Synonym of old chap (“the penis”) 

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