bakkie vs tractor-trailer

bakkie

noun
  • A small pick-up truck or ute, generally open and sometimes fitted with a removable canopy, but distinct from an enclosed van and a large truck. 

  • A small bowl or container, sometimes with a cover such as a Tupperware container. 

tractor-trailer

noun
  • A large truck consisting of an engine and cab section (the tractor) and a cargo-carrying semi-trailer or trailer. 

How often have the words bakkie and tractor-trailer occurred in a corpus of books? (source: Google Ngram Viewer )