agent general vs commissioner

agent general

noun
  • Specifically, the representative of a British colony or, later, of a Canadian province or Australian state in key cities abroad. 

commissioner

noun
  • An official in charge of a government department, especially a police force. 

  • Someone commissioned to perform certain duties. 

  • A member of a commission. 

  • Someone who commissions something. 

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