silence vs sit on

silence

verb
  • To suppress criticism, etc. 

  • To repress the expression of something. 

  • To block gene expression. 

  • To murder. 

  • To make (someone or something) silent. 

noun
  • deadly silence 

  • The act of refraining from speaking. 

  • The absence of any sound. 

intj
  • Be silent. 

sit on

verb
  • To block, suppress, restrain. 

  • To take no action on; to hold in reserve without actually using. 

  • To hold an official inquiry regarding; to deliberate about. 

  • To be a member of. 

  • Used other than figuratively or idiomatically: see sit, on. 

  • To restrain (a person). 

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