Sum column value : undefined

oldano97

I created a function to calculate the sum of a column value

$('#example').on('draw.dt', function(){
          var tot;
          table.rows().every(function(){
            totale += this.data().Guthaben;
          });
          $('#tot').html('Tot: ' + tot);
        });

the "Guthaben" field is a float type, but it returns me a string sum, like: 100.00200.0010.0020.00