magento summary rating of customers review in review list

put this code in(deault/default\template\review\product\view/list.phtml)
         <tbody>
                    <?php
                     $_percent = 0;
                    foreach ($_review->getRatingVotes() as $_vote){
                    $_percent = $_percent + $_vote->getPercent();
                    }
                      $_percent = $_percent / count($_review->getRatingVotes());?>
                    <tr>
                        <th class="label"><?php //echo $this->escapeHtml($_vote->getRatingCode()) ?>Aggregate rating:</th>
                        <td class="value">
                            <div class="rating-box">
                                <div class="rating" style="width:<?php echo  $_percent  ?>%;"></div>
                            </div>
                        </td>
                    </tr>
                    <?php //endforeach; ?>
                </tbody>


instead of

            <tbody>
                        <?php foreach ($_votes as $_vote): ?>
                        <tr>
                            <th><?php echo $this->escapeHtml($_vote->getRatingCode()) ?></th>
                            <td>
                                <div class="rating-box">
                                    <div class="rating" style="width:<?php echo $_vote->getPercent() ?>%;"></div>
                                </div>
                            </td>
                        </tr>
                        <?php endforeach; ?>
                    </tbody>