boycott vs thumbs down

boycott

noun
  • The act of boycotting. 

verb
  • To abstain, either as an individual or a group, from using, buying, or dealing with someone or some organization as an expression of protest. 

thumbs down

noun
  • A rejection or refusal. 

  • A gesture signifying disapproval; a thumb pointing down out of a fist. 

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