Accessibility: Table (complex with multiple levels of headers)

table-complex-level-headers.html

<table>
  <caption>Shelly's Daughters</caption>
    <tbody><tr>
      <td></td>
      <th scope="col">Name</th>
      <th scope="col">Age</th>
      <th scope="col">Birthday</th>
    </tr>
    <tr>
      <th rowspan="2" scope="row">by birth</th>
      <th scope="row">Jackie</th>
      <td>5</td>
      <td>April 5</td>
    </tr>
    <tr>
      <th scope="row">Beth</th>
      <td>8</td>
      <td>January 14</td>
    </tr>
    <tr>
      <th scope="row">by marriage</th>
      <th scope="row">Beth</th>
      <td>8</td>
      <td>January 14</td>
    </tr>
  </tbody>
</table>