futility vs unskillfulness

futility

noun
  • The quality of being futile or useless. 

  • Something, especially an act, that is futile. 

  • Unimportance. 

unskillfulness

noun
  • The state or quality of being unskillful, of lacking skill 

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