Calculate increase or decrease percentage between two number

I have two numbers of yesterday’s price and today’s price in the table. I want to display the price increase or decrease as a percentage next to today’s price number.

This is my table:

<table>
  <thead>
    <tr>
      <th>yesterday's price</th>
      <th>today's price</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>50</td>
      <td>75</td>
   </tr>
   <tr>
     <td>100</td>
     <td>50</td>
   </tr>
   <tr>
     <td>82</td>
     <td>82</td>
   </tr>
  </tbody>
</table>

I’m going to change it like this:

By adding what JavaScript codes can I make these changes in the table? Thanks for your help

<table>
  <thead>
    <tr>
      <th>yesterday's price</th>
      <th>today's price</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>50</td>
      <td class="increase">75 (+50% increase)</td>
   </tr>
   <tr>
     <td>100</td>
     <td class="decrease">50 (-50% decrease)</td>
   </tr>
   <tr>
     <td>82</td>
     <td class="nochange">82 (no change)</td>
   </tr>
  </tbody>
</table>