choice vs secret ballot

choice

intj
  • Cool; excellent. 

adj
  • Especially good or preferred. 

noun
  • One selection or preference; that which is chosen or decided; the outcome of a decision. 

  • Anything that can be chosen. 

  • The power to choose. 

  • Do I have a choice of what color to paint it? 

  • An option; a decision; an opportunity to choose or select something. 

  • The best or most preferable part. 

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 choice and secret ballot occurred in a corpus of books? (source: Google Ngram Viewer )