Silver vs Sky

Silver

name
  • A unisex given name from English from the metal, or transferred from the surname. 

  • An English surname originating as an occupation for a silversmith or a rich man, or for someone having silvery gray hair or living by a silvery brook. 

  • A surname from German. 

Sky

name
  • A unisex given name from English. 

  • A surname. 

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