Declare
        v_BaselineSize        number(20);
        v_CurrentSize        number(20);
        v_TotalGrowth        number(20);
        v_Space                number(20);
        cursor usageHist is
                select a.snap_id,
                        SNAP_TIME,
                        sum(TOTAL_SPACE_ALLOCATED_DELTA) over ( order by a.SNAP_ID) ProgSum
                from
                        (select SNAP_ID,
                                sum(SPACE_ALLOCATED_DELTA) TOTAL_SPACE_ALLOCATED_DELTA
                        from DBA_HIST_SEG_STAT
                        group by SNAP_ID
                        having sum(SPACE_ALLOCATED_TOTAL) <> 0
                        order by 1 ) a,
                        (select distinct SNAP_ID,
                                to_char(END_INTERVAL_TIME,'DD-Mon-YYYY HH24:Mi') SNAP_TIME
                        from DBA_HIST_SNAPSHOT) b
                where a.snap_id=b.snap_id;
Begin
        select sum(SPACE_ALLOCATED_DELTA) into v_TotalGrowth from DBA_HIST_SEG_STAT;
        select sum(bytes) into v_CurrentSize from dba_segments;
        v_BaselineSize := v_CurrentSize - v_TotalGrowth ;

        dbms_output.put_line('SNAP_TIME           Database Size(MB)');

        for row in usageHist loop
                v_Space := (v_BaselineSize + row.ProgSum)/(1024*1024);
                dbms_output.put_line(row.SNAP_TIME || '           ' || to_char(v_Space) );
        end loop;
end;