garden apartment vs granny annexe

garden apartment

noun
  • A detached mother-in-law apartment or cottage on the same parcel as the main house. 

  • An urban apartment in a multistory building located at or below ground level. 

  • One of a set of low-rise apartment buildings built among landscaped grounds and often arranged around courtyards that are open at one end. 

granny annexe

noun
  • An extension built to house an elderly relative. 

How often have the words garden apartment and granny annexe occurred in a corpus of books? (source: Google Ngram Viewer )