debouch vs pound the pavement

debouch

verb
  • To pour forth from a narrow opening; to emerge from a narrow place like a defile into open country or a wider space. 

noun
  • A fortress at the end of a defile. 

  • A narrow outlet from which a body of water pours. 

pound the pavement

verb
  • To travel on foot; to walk or run. 

  • To campaign diligently; to seek something, such as business, employment, or answers. 

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