how to use rowspan in html

<table>

        <tr>

    <th>Month</th>

    <th>Savings</th>

    <th>Savings for holiday!</th>

  </tr>

  <tr>

    <td>January</td>

    <td>$100</td>

    <td rowspan="2">$50</td>

  </tr>

  <tr>

    <td>February</td>

    <td>$80</td>

  </tr>

 </table>