bringing up the rear vs leading

bringing up the rear

leading

adj
  • Providing guidance or direction. 

  • Occurring in advance; preceding. 

  • Ranking first. 

noun
  • Vertical space added between lines; line spacing. 

  • An act by which one is led or guided. 

How often have the words bringing up the rear and leading occurred in a corpus of books? (source: Google Ngram Viewer )