Retrieve values from excel sheet

[sravsand]

In an excel sheet having many rows and columns, in this there are 2 columns those are
questionnumber | Answers
1 a
2 c
3 b
1 c
4 d
2 d
. .
. .

here my question is what is the percentage of answers for each question number,
Output ex:
QuestionNumber | a% | b%| c%| d%|
1 |50|0|50|0|
2 |0|0|50|50|

like this for all question numbers. and this result should be inserted in new excel sheet

Thanks inadvance