furtherance vs obstruction

furtherance

noun
  • Promotion. 

  • Advancement or progress. 

  • The act of furthering or helping forward 

obstruction

noun
  • Something which obstructs or impedes, either intentionally or unintentionally 

  • The act of obstructing, or state of being obstructed. 

  • The condition of having the natural powers obstructed in their usual course; the arrest of the vital functions; death. 

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