stall for time vs vacillate

stall for time

verb
  • To intentionally cause a delay; to stop; to wait. 

vacillate

verb
  • To swing indecisively from one course of action or opinion to another. 

  • To sway unsteadily from one side to the other; oscillate. 

How often have the words stall for time and vacillate occurred in a corpus of books? (source: Google Ngram Viewer )