difficulty vs presumption

difficulty

noun
  • That which cannot be easily understood or believed. 

  • Physical danger from the environment, especially with risk of drowning 

  • An obstacle that hinders achievement of a goal. 

  • The state of being difficult, or hard to do. 

  • An objection. 

  • An awkward situation or quarrel. 

presumption

noun
  • the belief of something based upon reasonable evidence, or upon something known to be true 

  • the condition upon which something is presumed 

  • the act of presuming, or something presumed 

  • An inference that a trier of fact is either permitted or required to draw under certain factual circumstances (as prescribed by statute or case law) unless the party against whom the inference is drawn is able to rebut it with admissible, competent evidence. 

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