nonchalance vs uneasiness

nonchalance

noun
  • Indifference, unconcern; carelessness; coolness; disregard, detachment. 

uneasiness

noun
  • The state of being uneasy, nervous or restless. 

  • An anxious state of mind; anxiety. 

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