Расчет количества строк столбца в экспорте в excel

procedure TForm1.btn2Click(Sender: TObject);
var XL,Sheet: Variant;
i : integer;
 
begin
XL:= CreateOleObject('Excel.Application');
XL.WorkBooks.Add;
Sheet:= XL.ActiveWorkBook.Sheets[1];
Sheet.PageSetup.Orientation:= 2;
Sheet.Name:= 'арп 1';
 
Sheet.Columns[1].ColumnWidth:= 10;
Sheet.Columns[2].ColumnWidth:= 20;
Sheet.Columns[3].ColumnWidth:= 9;
Sheet.Columns[4].ColumnWidth:= 35;
Sheet.Columns[5].ColumnWidth:= 13;
 
Sheet.Range[Sheet.Cells[1,2],Sheet.Cells[1,5]].HorizontalAlignment:= 3;
Sheet.Range[Sheet.Cells[1,2],Sheet.Cells[1,5]].VerticalAlignment:= 2;
Sheet.Range[Sheet.Cells[1,2],Sheet.Cells[1,5]].WrapText:= true;
Sheet.Range[Sheet.Cells[1,2],Sheet.Cells[1,5]].Font.FontStyle:= 'Полужирный';
Sheet.Range[Sheet.Cells[1,2],Sheet.Cells[1,5]].Merge(false);
Sheet.Range[Sheet.Cells[1,2],Sheet.Cells[1,5]]:= 'Отчет продаж билетов за период';
 
Sheet.Range[Sheet.Cells[2,2],Sheet.Cells[2,5]].HorizontalAlignment:= 3;
Sheet.Range[Sheet.Cells[2,2],Sheet.Cells[2,5]].VerticalAlignment:= 2;
Sheet.Range[Sheet.Cells[2,2],Sheet.Cells[2,5]].WrapText:= true;
Sheet.Range[Sheet.Cells[2,2],Sheet.Cells[2,5]].Font.FontStyle:= 'Полужирный';
Sheet.Range[Sheet.Cells[2,2],Sheet.Cells[2,5]].Merge(false);
Sheet.Range[Sheet.Cells[2,2],Sheet.Cells[2,5]]:= 'Проверил(а):______________';
 
Sheet.Cells[3,1]:= 'Код билета';
Sheet.Cells[3,2]:= 'Конечная';
Sheet.Cells[3,3]:= 'Цена';
Sheet.Cells[3,4]:= 'ФИО';
Sheet.Cells[3,5]:= 'Дата выезда';
 
i:= 4;
qry1.First;
while not qry1.Eof do
begin
Sheet.Cells[i,1]:= qry1.Fields[0].AsInteger;
Sheet.Cells[i,2]:= qry1.Fields[1].AsString;
Sheet.Cells[i,3]:= qry1.Fields[2].AsVariant;
Sheet.Cells[i,4]:= qry1.Fields[3].AsString;
Sheet.Cells[i,5]:= qry1.Fields[4].AsVariant;
 
 
inc(i);
qry1.Next;
end;
XL.Visible:= true;
Sheet:= UnAssigned;
XL:= UnAssigned;
end;