dataframe (e.g. linelist)</p></td>
    </tr>
    <tr>
      <th>age_group</th>
      <td><p>the name of a column in the data frame that defines the age
group categories. Defaults to "age_group"</p></td>
    </tr>
    <tr>
      <th>split_by</th>
      <td><p>the name of a column in the data frame that defines the
the bivariate column. Defaults to "sex". See NOTE</p></td>
    </tr>
    <tr>
      <th>stack_by</th>
      <td><p>the name of the column in the data frame to use for shading
the bars. Defaults to 