public function choices($reload = false)
 {
     if ($reload or !$this->choices_cache) {
         $id = mysql_real_escape_string($this->id);
         $this->choices_cache = SurveyAnswerChoice::find_all("survey_answers.id = '{$id}'");
     }
     return $this->choices_cache;
 }
 public function total_percentage()
 {
     $question_id = mysql_real_escape_string($this->question->id);
     $percent = count($this->choices()) / count(SurveyAnswerChoice::find_all("survey_questions.id = '{$question_id}'"));
     $percent *= 100;
     return round($percent);
 }