Accumulating Total.

I am trying to build a report with totals within a range. Below is the code am using:

Cont.SETRANGE("Employee No.",Empid);
Cont.SETRANGE("From Date","Period Start","Period End");
Cont.SETFILTER("From Date",'>=%1',"Period Start");
Cont.SETFILTER("To Date",'<=%1',"Period End");


IF Cont.FIND('-')
THEN BEGIN
TotalAmount += Cont.Quantity;
END;

Now when I run the report I am only getting one of the Amounts in the range and not the total.
Any ideas how to get the total of all occurring Amounts within the range please!