absenteeism vs unavailability

absenteeism

noun
  • The state of being absent, especially frequently or without good reason; the practice of an absentee. 

  • The practice of absenting oneself from the country or district where one's estate is situated. 

unavailability

noun
  • The state of being unavailable 

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