function myFunction() {

    var cells = document.getElementById('myTable').getElementsByTagName('td');

    var max = 6;
    var i = 2;

    for (x = 0; x < 10; x++) {
      var count = 0;
      var sum = 0;

      while (i <= max) {
        if (cells[i].innerHTML != "-") {
          sum += parseInt(cells[i].innerHTML);
        }
        i++;
      }
      cells[i].innerHTML = Math.round(sum/count) + "%";
      i += 3;
      max += 8;
        }
  }