Rebel vs trek

Rebel

noun

  • A Confederate soldier; of the Confederate States of America; of the American Civil War. 

trek

noun

  • The Boer migration of 1835-1837. 

  • A journey by ox wagon. 

  • A long walk. 

  • A slow or difficult journey. 

verb

  • To travel by ox wagon. 

  • To travel by walking. 

  • To journey on foot, especially to hike through mountainous areas. 

  • To make a slow or arduous journey. 

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