consider vs knock on wood

consider

verb
  • To think about something seriously or carefully: to deliberate. 

  • To believe or opine (that). 

  • To think about seriously. 

  • To have regard to; to take into view or account; to pay due attention to; to respect. 

  • To assign some quality to. 

  • To look at attentively. 

  • To think of doing. 

  • To take up as an example. 

  • To debate (or dispose of) a motion. 

knock on wood

verb
  • To take a customary action to ward off some misfortune that is believed to be attracted by a presumptuous statement. 

intj
  • Hopefully; a self-directive to undertake the customary action to ward off bad luck. 

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