merchant marine vs shipment

merchant marine

noun
  • A ship dedicated to commercial, rather than military, purposes. 

  • Synonym of merchant navy. The fleet considered as an entire combined force. 

shipment

noun
  • a load of goods that is transported by any method (not just by ship) 

  • the act of transporting goods 

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