Estimated Execution Plan SQL Server Sort?

I'm running a query and its taking a age to execute, looking at the execution plan I can see that 51% of the cost is in the SORT? when in the actual query i am not ORDERING BY anything. Anyone got any ideas how to get this SORT percentage down or remove it all together? Here is the query I'm running. SELECT Time_ID, Site_Type_ID, Abandoned_ID, WorkType_ID, SUM (staging.dbo.measure.ring_time) AS Ring_Time, SUM (staging.dbo.measure.hold_time) AS Hold_Time, SUM (staging.dbo.measure.talk_time) AS Talk_Time, SUM (staging.dbo.measure.acw_time) AS ACW_Time, COUNT(*) CallCount FROM measure INNER JOIN DataMartEnd.dbo.Time_Dim ON measure.StartTimeDate BETWEEN Time_Dim.Time_Start AND Time_Dim.Time_End INNER JOIN datamartend.dbo.Site_Type_Dim ON measure.DBID = Site_Type_Dim.Site_Type_Code INNER JOIN datamartend.dbo.Abandoned_Call_Dim ON measure.Abandoned = Abandoned_Call_Dim.abandoned_value INNER JOIN DataMartEnd.dbo.Work_Type_Dim ON measure.DBID = work_type_dim.MIG_Site_ID AND Work_Type_Dim.Work_Type_Code = measure.Queue AND measure.StartTimeDate BETWEEN Work_Type_Dim.DimEffectiveStartDtm AND Work_Type_Dim.DimEffectiveEndDtm GROUP BY Abandoned_ID, WorkType_ID, Site_Type_ID, time_id Thanks for the help.