loose change vs petty cash

loose change

noun
  • A sum of money considered small or insignificant. 

  • Coins of little value kept in one's pocket or bag. 

petty cash

noun
  • Cash available for trivial purchases, especially limited funds for employees to use without close supervision. 

How often have the words loose change and petty cash occurred in a corpus of books? (source: Google Ngram Viewer )