duo vs man and wife

duo

noun
  • Any pair of two people. 

  • Two people who work or collaborate together as partners; especially, those who perform music together. 

  • Any cocktail consisting of a spirit and a liqueur. 

  • A song in two parts; a duet. 

man and wife

noun
  • An opposite-sex married couple. 

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