back forty vs backwoods

back forty

noun
  • The most remote or inaccessible part of any place. 

  • The remote part of a farm. 

backwoods

noun
  • A remote or sparsely inhabited region, especially in North America; away from big towns and from the influence of modern life. 

  • Partly or wholly uncleared forest, especially in North America. 

adj
  • Rough, uncouth, coarse, or crude in social matters. 

  • Pertaining to the backwoods. 

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