niceness vs unpleasantness

niceness

noun
  • A value determining how much processor time to concede to a running process. (See also nice (verb), renice.) 

  • Effeminacy; indulgence in soft living or luxuriousness. 

  • Fastidiousness; fine sensitivity. 

  • Pleasantness, especially of behaviour or personality; agreeableness. 

unpleasantness

noun
  • An unpleasant behaviour, occurrence, etc. 

  • The property of being unpleasant or disagreeable. 

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