Hi Maulik,
Interesting question!
I cannot imagine a simple way to reply to this question but if someone has any idea, I'll read it with interest.
Instead, I would answer with a three steps approach:
1. Extract informations about workflows in a structure made of database tables.
2. Enquiry the tables to have the results you need.
3. Create a report on that data and publish it into Alfresco.
Point 1 could be solved using the Alfresco's REST services into a database table.
Point 2 could be solved making a SQL query on the target table (or a procedure to prepare another target table, more organized to store the informations with the structure you need).
Point 3 could be solved using AAAR or any other custom solution you will could easily develop.
I hope this will help you.