Set Subtotals to true to add a row or column of subtotals following the last value of the dimension. The subtotal row or column contains values of the summary field summarized over all values in the dimension. Set Subtotals to false to omit the subtotal row or column at the end of the dimension. 

To turn subtotals on or off for all dimensions in the grid at once, use the Totals property of the decision grid. 

Totals