recommendation vs refusal

recommendation

noun
  • An act of recommending. 

  • A suggestion or proposal about the best course of action (with adpositions including "about" for the context and "to" for the course of action) 

  • That which is recommended. 

  • A commendation or endorsement. 

refusal

noun
  • The act of refusing. 

  • Depth or point at which well or borehole drilling cannot continue. 

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