case officer vs receptionist

case officer

noun
  • A person assigned to manage a client's affairs. 

  • In intelligence organisations, a person who manages a network of agents. 

receptionist

noun
  • An employee (such as a secretary) who works in reception (receiving visitors and/or calls) for a person or business, especially an office. 

  • A proponent of receptionism. 

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