Add new row with values which are sum of above rows

Hi All,
I have a scenario where I pull sales data for multiple states and display in gridview.
I am achieving this by writing a stored procedure and binding the rows returned with gridview. 
My requirement is along with the data from stored proc. I want a new row after ever state data and this is sum of values for a state.
EX
State  AgentID Sales  Goal Time  
1         101       100   150     10                     <---------- From stored proc
1        102        90     100     8                          <--- From stored proc
s1       s1         190   250      18                 ...