cohabitation vs domestic partnership

cohabitation

noun
  • An emotional and physical intimate relationship which includes a common living place and which exists without legal or religious sanction. 

  • A place where two or more individuals reside together. 

  • The act of living together. 

  • The act of two species living together in the same habitat. 

  • Cooperation between politicians of opposing political parties; especially, in France, between a President and Prime Minister. 

domestic partnership

noun
  • A legal or personal relationship between individuals who live together and share a common domestic life but are not joined in a traditional marriage or a civil union. Typically the partners in a domestic partnership enjoy at least part of the rights that the married couples have. 

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