Percent completed progress bar

Hi experts, Does anyone have a sample code or link to working code on how to build progress bar that shows percentage of response completed? We have a quiz with varying questions. All the questions don't have the same number. For instance, some questions are only 5; some are 10 and some may be more than 10 . Assume that there are 10 questions, each time a user selects one question, it shows % on progress bar. All questions are radio buttons choices. Thanks a lot in advance ...