Datatable count all the different varieties

In my datatable I am trying to count all the different varieties of a column. In the sample below I want the output to count yes,no and then add all the yes no together. I tried the fnFooterCallback but I am not getting the values?

Output 
Yes 1
No  2
Total Votes (Y+N)   3


var table = $('#question').dataTable();
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.0/jquery.min.js"></script>
<script src="http://cdn.datatables.net/1.10.18/js/jquery.dataTables.min.js"></script>
<table id="question">
  <tr>
    <th>Question 1</th>
    <th>Question 2</th>
    <th>Question 3</th>
  </tr>
  <tr>
    <td>Yes</td>
    <td>Hot</td>
    <td>Yes</td>
  </tr>
  <tr>
    <td>No</td>
    <td>Cold</td>
    <td>Yes</td>
  </tr>
  <tr>
    <td>No</td>
    <td>Hot</td>
    <td>Yes</td>
  </tr>
</table>