Html – How to style table to be full width of container and make the cells use percentage of the width

This is my html. The table below is inside a container div which has fixed width of 670px. Now I am not sure how to proceed to make this table capture the full width of container.

<table class="table_fields">
    <tr class="table_fields_top">
        <td><?php _e('Published','news'); ?></td>
        <td><?php _e('Story','news'); ?></td>
        <td><?php _e('Views','news'); ?></td>
        <td><?php _e('Comments','news'); ?></td>
        <td><?php _e('Rating','news'); ?></td>
    </tr>
</table>

This is my CSS:

.table_fields {
    display: block;
    background: #fff;
    border: 1px solid #dce1e9;
    border-bottom: 0;
    border-spacing: 0;
}

.table_fields .table_fields_top {background: #f1f3f6;}
.table_fields .table_fields_top td{
    font-size: 10px;
    text-transform: uppercase;
}

.table_fields td {
    text-align: center;
    border-bottom: 1px solid #dce1e9;
    border-right: 1px solid #dce1e9;
    font-size: 11px;
    line-height: 16px;
    color: #666;
    white-space:nowrap;
}

I tried to set width: 100%; but it returned empty spaces but the TDs are not balanced. I do not know how to make the TDs always full 100% of the space. I tried to set width: 20% for each TD since they are 5 tds to receive 100% width. But this didn't work. Can someone tell me how to make the cells fit in the FUll width of table 100% (given each TD has a fixed percentage of width like 20%) please.