litany vs recurrence

litany

noun
  • A prolonged or tedious list. 

  • A ritual liturgical prayer in which a series of prayers recited by a leader are alternated with responses from the congregation. 

recurrence

noun
  • The instance of recurring; frequent occurrence. 

  • A return of symptoms as part of the natural progress of a disease. 

  • Recourse. 

  • Return or reversion to a certain state. 

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