boycott vs work-to-rule

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. 

work-to-rule

noun
  • A labor protest in which employees do only the minimum work required by the rules of a workplace, following safety or other regulations to the letter in order to cause a slowdown. 

adj
  • Of or pertaining to such a protest. 

How often have the words boycott and work-to-rule occurred in a corpus of books? (source: Google Ngram Viewer )