back forty vs bumfuck nowhere

back forty

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

  • The remote part of a farm. 

bumfuck nowhere

name
  • The middle of nowhere; a nondescript, isolated, and underdeveloped locale whose precise location may be difficult to ascertain. 

  • I can't believe we're lost in the middle of bumfuck nowhere with a broken-down car! 

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