C#.NET ติดปัญหา divide by zero. ในการคำนวนตัวเลขใน Gridview ครับ

        decimal totalSum01_jul = 0M;
        decimal totalSum02_jul = 0M;
        decimal totalSum03_jul = 0M;
        decimal totalSum04_jul = 0M;

protected void myGridview_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            
            int totalItems = 0;

            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                Label Sum01 = (Label)e.Row.FindControl("lbBudget_jul");
                Label Sum02 = (Label)e.Row.FindControl("lbActual_jul");
                Label Sum03 = (Label)e.Row.FindControl("lbIn_jul");
                Label Sum04 = (Label)e.Row.FindControl("lbTurnover_jul");

                decimal Column01 = Convert.ToDecimal(DataBinder.Eval(e.Row.DataItem, "budget_jul").ToString());
                decimal Column02 = Convert.ToDecimal(DataBinder.Eval(e.Row.DataItem, "actual_jul").ToString());
                decimal Column03 = Convert.ToDecimal(DataBinder.Eval(e.Row.DataItem, "in_jul").ToString());
                decimal Column04 = Convert.ToDecimal(DataBinder.Eval(e.Row.DataItem, "turnover_jul").ToString());

                totalSum01_jul += Column01;
                totalSum02_jul += Column02;
                totalSum03_jul += Column03;
                totalSum04_jul += Column04;

                totalItems += 1;
            }

            if (e.Row.RowType == DataControlRowType.Footer)
            {
                Label Sum01 = (Label)e.Row.FindControl("lbtotalBudget_jul");
                Label Sum02 = (Label)e.Row.FindControl("lbtotalActual_jul");
                Label Sum03 = (Label)e.Row.FindControl("lbtotalIn_jul");
                Label Sum04 = (Label)e.Row.FindControl("lbtotalTurnover_jul");
                Label Sumtotal = (Label)e.Row.FindControl("lbtotalPercent_jul");

                Sum01.Text = totalSum01_jul.ToString();
                Sum02.Text = totalSum02_jul.ToString();
                Sum03.Text = totalSum03_jul.ToString();
                Sum04.Text = totalSum04_jul.ToString();

                Sumtotal.Text = (totalSum04_jul * (100) / totalSum02_jul).ToString("N2");
            }
        }