heedlessness vs slowness

heedlessness

noun
  • The state or character of being heedless 

slowness

noun
  • The quality or state of being slow. 

  • A unit, the reciprocal of velocity, that delineates the amount of time required for an object to travel a given distance. 

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