apple of someone's eye vs treasure

apple of someone's eye

noun
  • A favourite, a particular preference, or a loved one; the object of somebody's affections. 

treasure

noun
  • Anything greatly valued. 

  • A term of endearment. 

  • A collection of valuable things; accumulated wealth; a stock of money, jewels, etc. 

verb
  • To store or stow in a safe place. 

  • To consider to be precious; to value highly. 

How often have the words apple of someone's eye and treasure occurred in a corpus of books? (source: Google Ngram Viewer )