cenacle vs grouping

cenacle

noun
  • A small circle or gathering of specialists (writers etc). 

  • A dining room, especially one on an upper floor (traditionally the room in which the Last Supper took place). 

grouping

noun
  • A collection of things or people united as a group. 

  • The action of the verb to group. 

  • Shot grouping. 

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