how to add 2 last row in footer ?

intprotest

hello
https://codepen.io/intprotest/pen/XvbVqa?editors=0010

footerCallback: function(tfoot, data, start, end, display) {
  var api = this.api();
  var lastRow = api.rows().count();
  for (i = 0; i < api.columns().count(); i++) {
    $(tfoot).find('th').eq(i).html(api.cell(lastRow-2,i).data());


  } }, 

i want 11 and 12 row in footer ( i know html data but i don't have html data )
Thanks !

intprotest

how to add ?