chief executive vs chief minister

chief executive

noun

  • The governor of a U.S. state. 

  • Chief executive officer. 

  • The president of the United States. 

  • The head of government of Hong Kong 

  • The head of government of Macau 

chief minister

noun

  • The leader of government in many semi-autonomous and constituent federal states. 

How often have the words chief executive and chief minister occurred in a corpus of books? (source: Google Ngram Viewer )