Breakdown of total percentage in matrix

Hi I am amending a report that wasn't created by me.

I have a matrix table that looks like this (month is the column group and code is the data value

Columns
Month
Code(Sum(field.value)),Sum(Field2.value))

This brings back the following

Mar  Apr       May    Jun     Jul     Aug   Sep

0%  100%   0%     0%     33%   0%    32%

What I would like to do is to break these percentages down by a row group. but When I add a row group to the matrix it doesn't give the rigth values

This is how I would like it to look

           Mar Apr      May    Jun    Jul       Aug     Sep

Ins1     0%  80%    0%     0%    23%    0%      15%

Ins2     0%  20%    0%     0%    10%    0%      17%

 Total   0%  100%   0%     0%    33%    0%     32%   

Any help would be greatly appreciated.

Regards