I have got a call from one of my colleague saying that how to increase no of days for workload in st03n. This time is a new question for me so i find the solution for the same.
Go to ST03n
Present Value
How to Change:
1. Change to expert mode – 
2. Go to Collector & Performance DB
3. Open Control —
4. Change the value of:
Daily = 30 (as required)
Weekly = (as required)
Monthly = (as require)
save the entry.
Now you are Done..