break the bank vs improve

break the bank

verb
  • To exhaust one's financial resources. 

  • At a casino etc., to win all the money that is available to be paid. 

improve

verb
  • To make (something) better; to increase the value or productivity (of something). 

  • To become better. 

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