incompetence vs qualification

incompetence

noun
  • Inability to perform; lack of competence; ineptitude. 

qualification

noun
  • An ability or attribute that aids someone's chances of qualifying for something; specifically, completed professional training. 

  • The act or process of qualifying for a position, achievement etc. 

  • A clause or condition which qualifies something; a modification, a limitation. 

  • A certificate, diploma, or degree awarded after successful completion of a course, training, or exam. 

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