C-suite vs CXO

C-suite

noun
  • The group of officers of a business organization who have the word "chief" in their titles. 

  • Senior headquarters executives. 

CXO

noun
  • “chief X officer”, with X as functional placeholder (finance, operating etc.) 

How often have the words C-suite and CXO occurred in a corpus of books? (source: Google Ngram Viewer )