Preciso fazer a somatória em colunas

    <?php foreach ($naturezas as $chave => $valor) :  ?>
        <?php for ($v = 0; $v < 13; $v++) : ?>
            <?php if($v == 0) : ?>
                <tr><td>TITULO DA CATEGORIA</td>
            <?php else : ?>
                <td width="80" data-point="<?php echo $v ?>"><?php echo $v ?></td>
            <?php endif; ?>
        <?php endfor; ?>
    <?php endforeach ?>