porterage vs transshipment

porterage

noun
  • The carrying or transportation of goods by a porter (“person who carries luggage and related objects”) or other person. 

  • The charge for such carrying or transportation. 

  • The occupation of, or services provided by, a porter (“person in control of the entrance to a building”). 

  • Porters regarded collectively. 

transshipment

noun
  • The transfer of goods from one means of transport to another. 

  • The shipment of goods via an intermediate destination. 

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