drink like a fish vs knock back

drink like a fish

verb
  • To drink (especially alcohol) heavily and in excess. 

knock back

verb
  • To drink an alcoholic beverage swiftly or often. 

  • To stun; to surprise. 

  • To press or knead (dough) so as to remove air bubbles. 

  • To reject; to refuse. 

How often have the words drink like a fish and knock back occurred in a corpus of books? (source: Google Ngram Viewer )