power off vs pull off

power off

verb
  • To turn off, to cut the power to. 

pull off

verb
  • To turn off a road (onto the side of the road, or onto another road). 

  • To begin moving and then move away; to pull away. 

  • To masturbate. 

  • To remove by pulling. 

  • To achieve; to succeed at something difficult. 

How often have the words power off and pull off occurred in a corpus of books? (source: Google Ngram Viewer )