furtherance vs promotion

furtherance

noun
  • Advancement or progress. 

  • Promotion. 

  • The act of furthering or helping forward 

promotion

noun
  • An advancement in rank or position. 

  • An event intended to increase the reach or image of a product or brand. 

  • Transformation of a pawn into a piece (by reaching the opponent's back rank). 

  • Dissemination of information in order to increase its popularity. 

  • Forward motion. (Contrast remotion.) 

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