knapsack vs saddlebag

knapsack

noun
  • A case of canvas or leather, for carrying items on the back. 

  • A set of values from which a subset is chosen. 

verb
  • To go hiking while burdened with a knapsack, usually overnight or for longer. 

saddlebag

noun
  • A covered pouch, usually one of a pair, laid across the back of a horse, donkey, or mule behind its saddle, or hanging over the rear wheel of a bicycle or motorcycle; often made of leather or (on a bicycle or motorcycle) a rigid material. 

  • Loose fatty flesh on a person's upper thighs or buttocks, that hangs like saddlebags. 

  • A style of house with two rooms separated by a small hall and open space. 

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