code: function(groupName, totalSites, totalPages,
                                  totalPageviews) {
              var format = d3.format(',d');
              // build
              var summary = 
                '<tr>' +
                '<td>' + groupName + '</td>' +
                '<td>' + format(totalPageviews) + '</td>' +
                '<td>' + format(totalPages) + '</td>' +
                //'<td>' + totalSites + '</td>' +
                '</tr>';
  
              return summary;
          }
docs: build row for each table..
  
  <tr>
  <td>MOF</td>
  <td>2089</td>
  <td>345</td>
  </tr>