ignore vs knock back

ignore

verb
  • To deliberately not listen or pay attention to. 

  • To pretend to not notice someone or something. 

knock back

verb
  • To reject; to refuse. 

  • To drink an alcoholic beverage swiftly or often. 

  • To stun; to surprise. 

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

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