board member vs chief executive officer

board member

noun
  • a member of the board of directors of an association or company. 

chief executive officer

noun
  • The highest-ranking corporate officer or executive officer of a corporation, company, or agency, responsible for carrying out the policies of the board of directors on a day-to-day basis; CEO. 

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