T-SQL (SS2K8) :: How To Calculate Total Sum Of Values Of Table

I've the table like

create table accutn_det
(
fs_locn char(50),
fs_accno varchar(100),
fs_cost_center varchar(100),
fs_tran_type char(50)

[Code] .....

Like all location details stored from all months in these table

here Dr=debit,Cr=Credit Formula= 'Dr-Cr' to find the salary wavges of amount

so i made the query to find the amount for may

select
fs_locn,
fs_accno,
amount=sum(case when fs_accno like 'E%' and fs_tran_type='Dr' then fs_amount
when fs_accno like 'E%' and fs_tran_type='Cr' then fs_amount * -1
end
)
from
accutn_det where fs_trans_date between '01-may-2014' and '31-may-2014'
groupby fs_locn,fs_accno

now i need the sum values of all costcenter for the particular account.how to do that?