pirater vs privateer

pirater

noun
  • One who pirates (produces unauthorized copies). 

privateer

noun
  • An officer or any other member of the crew of such a ship; a government-sanctioned pirate. 

  • An advocate or beneficiary of privatization of a government service or activity. 

  • A privately owned warship that acted under a letter of marque to attack enemy ships and take possession of their cargo. 

  • A private individual entrant into a race or competition who does not have the backing of a large, professional team. 

  • A racing team that is not a subsidiary of a large conglomerate, or automotive/vehicle manufacturer. 

verb
  • To function under official sanction permitting attacks on enemy shipping and seizing ship and cargo; to engage in government-sponsored piracy. 

  • To advocate or benefit from privatization of government services. 

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