/**
  * calculate the absolute probability based on the (possibly) relative value in the config
  */
 private function get_probability($string_value, CRM_Banking_BAO_BankTransaction $btx)
 {
     if (substr($string_value, -1) === "%") {
         // if the value ends in '%' it's meant to be relative to the least probable suggestion
         $suggestion_list = $btx->getSuggestionList();
         $least_probable = end($suggestion_list);
         if ($least_probable) {
             $least_probable_value = $least_probable->getProbability();
         } else {
             $least_probable_value = 1;
         }
         return $least_probable_value * substr($string_value, 0, strlen($string_value) - 1) / 100.0;
     } else {
         // in the default case, we just assume it's an absolute value anyways...
         return $string_value;
     }
 }