How to identify how many users have chosen an option in multiple choice answer type questions?

I would like to show the quiz-taker how many people chose a particular option after each question. This presents me with 2 difficulties

1. How to compute what percentage of users chose which answer choice.
2. How to add an "in-between" page where only this information is displayed? I am trying to recreate the quiz functionality seen on http://www.lifescript.com/Quizzes/Astrology/Are_You_True_To_Your_Zodiac_... where, after you answer the question, immediately you are presented with the information "You Said ... Others Said ..."?
3. Also I would like to present to user how many people have "taken" a quiz. How can I compute that?

Thanks much.
- Srikanth.