convener vs manager

convener

noun
  • One who convenes or calls a meeting 

manager

noun
  • An administrator, for a singer or group. 

  • A person whose job is to manage something, such as a business, a restaurant, or a sports team. 

  • A window or application whose purpose is to give the user the control over some aspect of the system. 

  • The head coach. 

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