bluejacket vs water dog

bluejacket

noun
  • An enlisted man in the US Navy. 

  • A seaman of a British warship 

  • A uniformed policeman. 

water dog

noun
  • A retriever type of gun dog bred to flush and retrieve game from water. 

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