promptness vs slowness

promptness

noun
  • The habit of adhering to a designated time. 

  • The habit or characteristic of doing things without delay. 

slowness

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

  • The quality or state of being slow. 

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