duffel bag vs satchel

duffel bag

noun
  • A large, cylindrical, duffel cloth bag used to carry personal gear, especially by soldiers. 

  • A smaller, cylindrical, cloth bag fashionable in the 1950s and 1960s. 

satchel

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

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