Calculated field for cell value divided by table total

I am looking for a calculated field for cell value divided by table Grand Ttal

for example

ABC DEF

1 , 2

2, 2

3 , 4

4, 4

5, 6

---- ----

15 , 18

Table Grand Total is 15+18 = 33

So I need

ABC DEF

1/33, 2/33

2/33 , 2/33

3/33 and so on

Kindly help

Thanks