circumstance vs facts of life

circumstance

verb
  • To place in a particular situation, especially with regard to money or other resources. 

noun
  • An event; a fact; a particular incident. 

  • Circumlocution; detail. 

  • Something which is related to, or in some way affects, a fact or event. 

  • Condition in regard to worldly estate; state of property; situation; surroundings. 

facts of life

noun
  • knowledge of sexual reproduction (almost always used with the) 

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