commercial bank vs savings bank

commercial bank

noun
  • A bank whose chief business is accepting demand deposits and making short-term loans. 

savings bank

noun
  • A type of financial institution that focuses on retail banking: savings of private depositors, payments, credits and insurances for individuals or small and medium-sized enterprises. 

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