say no vs turn down

say no

verb
  • To reject something. 

  • To disagree; to think something or someone is doing or saying what is wrong. 

turn down

verb
  • To refuse, decline, or deny. 

  • To reduce the power, etc. of something by means of a control, such as the volume, heat, or light. 

  • To reposition by turning, flipping, etc. in a downward direction; to double or fold down. 

How often have the words say no and turn down occurred in a corpus of books? (source: Google Ngram Viewer )