cargo vs contents

cargo

noun
  • Freight carried by a ship, aircraft, or motor vehicle. 

  • Western material goods. 

contents

noun
  • That which is contained. 

  • A table of contents, a list of chapters, etc. in a book, and the page numbers on which they start. 

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