administrator vs case officer

administrator

noun
  • One who administers affairs; one who directs, manages, executes, or dispenses, whether in civil, judicial, political, or ecclesiastical affairs; a manager 

  • A person who manages or settles the estate of an intestate, or of a testator when there is no competent executor; one to whom the right of administration has been committed by competent authority 

  • One who is responsible for software installation, management, information and maintenance of a computer or network 

case officer

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

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

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