SELECT DECODE (state
              , 0, 'free'
              , 1, 'exclusive'
              , 2, 'shared current'
              , 3, 'consistent read'
              , 4, 'being read from disk'
              , 5, 'in media recovery mode'
              , 6, 'in instance recovery mode'
               ,state) "Block Status"
      , Count(1) "Count"
FROM x$bh
GROUP BY DECODE (state
              , 0, 'free'
              , 1, 'exclusive'
              , 2, 'shared current'
              , 3, 'consistent read'
              , 4, 'being read from disk'
              , 5, 'in media recovery mode'
              , 6, 'in instance recovery mode'
               ,state)
/