burden vs promote

burden

verb
  • To encumber with a literal or figurative burden. 

  • To impose, as a load or burden; to lay or place as a burden (something heavy or objectionable). 

noun
  • A phrase or theme that recurs at the end of each verse in a folk song or ballad. 

  • The proportion of ore and flux to fuel, in the charge of a blast furnace. 

  • The capacity of a vessel, or the weight of cargo that she will carry. 

  • A responsibility, onus. 

  • The tops or heads of stream-work which lie over the stream of tin. 

  • A fixed quantity of certain commodities. 

  • Theme, core idea. 

  • The drone of a bagpipe. 

  • A cause of worry; that which is grievous, wearisome, or oppressive. 

  • The total amount of toxins, parasites, cancer cells, plaque or similar present in an organism. 

  • A heavy load. 

promote

verb
  • To encourage, urge or incite. 

  • To increase the activity of (a catalyst) by changing its surface structure. 

  • To elevate to a higher league. 

  • To raise (someone) to a more important, responsible, or remunerative job or rank. 

  • To move on to a subsequent stage of education. 

  • To advocate or urge on behalf of (something or someone); to attempt to popularize or sell by means of advertising or publicity. 

  • To exchange (a pawn) for a queen or other piece when it reaches the eighth rank. 

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