trekker vs wanderer

trekker

noun
  • One who treks; a hiker. 

  • A person who spent the night in a rural area, rather than his home, during bombing raids. 

wanderer

noun
  • One who wanders, who travels aimlessly. 

  • Any of various far-migrating nymphalid butterflies of the genus Danaus. 

  • The wandering albatross, Diomedea exulans. 

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