immune (to) vs phlegmatic

immune (to)

phlegmatic

adj
  • Generating, causing, or full of phlegm. 

  • Not easily excited to action or passion; calm; sluggish. 

noun
  • One who has a phlegmatic disposition. 

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