commissioner vs senator

commissioner

noun
  • An official in charge of a government department, especially a police force. 

  • Someone commissioned to perform certain duties. 

  • A member of a commission. 

  • Someone who commissions something. 

senator

noun
  • A member of the ruler’s council or governing council in general, a leading statesman. 

  • A member, normally elected, in the house or chamber of a legislature called a senate, as, for instance, the legislatures of the United States and Canada. 

  • A member of the ancient Roman Senate. 

  • A member of a governing council in other states in the ancient world. 

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