ax to grind vs preoccupation

ax to grind

noun
  • A proposition or point of view to advocate, especially motivated by self-interest. 

  • A grudge or grievance, with implications of confrontation. 

preoccupation

noun
  • The state of being preoccupied or an idea that preoccupies the mind; enthrallment. 

  • The act of occupying something before someone else. 

How often have the words ax to grind and preoccupation occurred in a corpus of books? (source: Google Ngram Viewer )