coterie vs inner circle

coterie

noun
  • A circle of people who associate with one another for a common purpose. 

  • A communal burrow of prairie dogs. 

inner circle

noun
  • The group comprising one's closest friends or associates. 

  • Used other than figuratively or idiomatically: see inner, circle. 

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