cob roller vs piggy

cob roller

piggy

noun

  • A toe. 

  • A pig, a greedy person. 

  • A member of the police. 

  • A pig (the animal). 

  • A guinea pig. 

adj

  • slovenly, dirty 

  • greedy 

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