small change vs small potatoes

small change

noun
  • A person or thing of little importance or value. 

  • A minor or insignificant amount of money. 

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

small potatoes

noun
  • One or more persons or things of relatively little consequence, importance, or value. 

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