continental quilt vs covers

continental quilt

noun
  • A duvet used in combination with other blankets. 

covers

noun
  • The bedclothes; collectively, the sheets, blankets, etc. 

  • The tarpaulins or other devices used to cover the wicket during rain, in order to prevent it getting wet. 

  • The area of the field near cover and extra cover. 

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