backyard vs patio

backyard

noun
  • A yard to the rear of a house or similar residence. 

  • An area nearby to a country or other jurisdiction's legal boundaries, particularly an area in which the country feels it has an interest. 

  • A person's neighborhood, or an area nearby to a person's usual residence or place of work and where the person is likely to go. 

patio

noun
  • A paved outside area, adjoining a house, used for dining or recreation. 

  • An inner courtyard typical of traditional houses in some regions of Spain. 

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