stoppage vs work-to-rule

stoppage

noun
  • Something that forms an obstacle to continued activity; a blockage or obstruction. 

  • A pause or halt of some activity. 

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 stoppage and work-to-rule occurred in a corpus of books? (source: Google Ngram Viewer )