chief minister vs minister-president

chief minister

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

minister-president

noun
  • The head of government in a number of European countries or subnational governments, in which a parliamentary or semi-presidential system of government prevails, who presides over the council of ministers. 

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