helpmate vs viscountess

helpmate

noun
  • A wife or spouse. 

  • A person who supplies help or companionship. 

  • A recreational problem in chess in which both sides cooperate to achieve a specific goal. 

viscountess

noun
  • The wife of a viscount. 

  • A woman holding the rank of viscount in her own right. 

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