cool down vs take it easy

cool down

verb
  • To become less agitated or excited. 

  • To become cooler; to be reduced in temperature. 

  • To cause (something) to become cooler; to reduce the temperature of. 

  • To decrease in degree or intensity. 

  • To cause (someone) to become less agitated or excited. 

take it easy

verb
  • To relax or rest. 

  • A farewell (for parting or closing). 

How often have the words cool down and take it easy occurred in a corpus of books? (source: Google Ngram Viewer )