php - TCPDF: Rotate text in HTML table

one text

I have a problem. Trying to rotate text in table, which I created like this:

$tbl = '<table border="1" style="text-align: center;">
  <tr>
    <th rowspan="2">Year, month, day</th>
    <th rowspan="2">Person</th>
  </tr>
</table>';
$pdf->writeHTML($tbl_4, true, false, false, true, '');

I want to rotate first "th" 90 degrees, I mean set text from bottom to top, like in this photo.

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