litany vs orison

litany

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

  • A prolonged or tedious list. 

orison

noun
  • A prayer. 

  • Mystical contemplation or communion. 

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