bottom line vs crux

bottom line

noun
  • The summary or result; the most important information. 

  • A minimum acceptable result from a negotiation. 

  • The final balance; the amount of money or profit left after everything has been tallied. 

crux

noun
  • The basic, central, or essential point or feature. 

  • The critical or transitional moment or issue, a turning point. 

  • The hardest point of a climb. 

  • A puzzle or difficulty. 

  • A cross on a coat of arms. 

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