High water mark | Query

SELECT

                TABLE_NAME, LAST_ANALYZED, BLOCKS, NUM_ROWS,

                ROUND(((BLOCKS*8192/(1024*1024)))) "TOTAL_SIZE",

                ROUND((NUM_ROWS*AVG_ROW_LEN/1024/1024)) "ACTUAL_SIZE",

                ROUND(((BLOCKS*8192/(1024*1024))-(NUM_ROWS*AVG_ROW_LEN/1024/1024))) "FRAGMNTD",

                ROUND((((BLOCKS*8192/(1024*1024))-(NUM_ROWS*AVG_ROW_LEN/1024/1024))/((BLOCKS*8192/(1024*1024))))*100) "% FRAGMNTD"

FROM

                DBA_TABLES

ORDER BY 8 DESC;