walk out vs work to rule

walk out

verb
  • To stage a walkout or strike. 

  • To step away with when carrying the weight in order not to hit the rack it was lifted off from during execution of the exercise. 

  • To leave suddenly, especially as a form of protest. 

  • To continue or persist in carrying (something) out or following through (with something); to persevere. 

  • To accompany (someone) as they leave a house or other building. 

work to rule

verb
  • To work slowly by strictly following all work rules, usually in a work-to-rule job action, as part of unionized labor protest. 

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