aye vs secret ballot

aye

noun
  • An affirmative vote; one who votes in the affirmative. 

intj
  • an attention grabber 

  • yes; yea; a word expressing assent, or an affirmative answer to a question. 

  • a word used to acknowledge a command from a superior, usually preceded by a verbatim repeat-back. 

secret ballot

noun
  • The voting system involving ballots available only at official polling places, prepared at public expense, containing the names of all candidates, and marked in secret at the polling places. 

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