billfold vs satchel

billfold

noun
  • A small, folding sleeve or case designed to hold paper currency, as well as credit cards, pictures, etc. 

satchel

noun
  • A bag or case with one or two shoulder straps, especially used to carry books etc. 

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