at a rate of knots vs hotfoot

at a rate of knots

prep
  • Quickly; rapidly; fast. 

hotfoot

verb
  • To run (a distance). 

noun
  • The prank of secretly inserting a match between the sole and upper of a victim's shoe and then lighting it. 

adj
  • Moving with haste or zeal. 

adv
  • Hastily; without delay. 

How often have the words at a rate of knots and hotfoot occurred in a corpus of books? (source: Google Ngram Viewer )