nonchalance vs presence of mind

nonchalance

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

presence of mind

noun
  • Focused alertness, quick-thinking resourcefulness, stability of thought and feeling, or good sense, especially in spite of circumstances which are distracting, stressful, or otherwise challenging. 

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