minder vs ombudsman

minder

noun
  • A monitor assigned by the authorities to someone, such as a foreign visitor (to exercise control over their contacts with the populace) or a journalist or someone who is speaking to journalists (to monitor and control what they say). 

  • One who minds, tends, or watches something such as a child, a machine, or cattle; a keeper. 

  • A personal bodyguard. 

ombudsman

noun
  • A designated internal mediator in an organization whose duty is to assist members with conflict resolution and other problems and to serve as an independent consultant to recommend changes to policies or procedures to improve organization effectiveness, efficiency, and humaneness. 

  • An appointed official whose duty is to investigate complaints, generally on behalf of individuals such as consumers or taxpayers, against institutions such as companies and government departments. 

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