anxiety vs difficulty

anxiety

noun
  • An uneasy or distressing desire (for something). 

  • An unpleasant state of mental uneasiness, nervousness, apprehension and obsession or concern about some uncertain event. 

  • A state of restlessness and agitation, often accompanied by a distressing sense of oppression or tightness in the stomach. 

difficulty

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

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

  • An obstacle that hinders achievement of a goal. 

  • An objection. 

  • An awkward situation or quarrel. 

  • That which cannot be easily understood or believed. 

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