cool as a cucumber vs unemotional

cool as a cucumber

adj
  • Calm and composed even in difficult or frustrating situations; self-possessed. 

unemotional

adj
  • Reasoned and objective, involving reason or intellect rather than feelings. 

  • Showing little or no feeling. 

How often have the words cool as a cucumber and unemotional occurred in a corpus of books? (source: Google Ngram Viewer )