latch_hit_ratios script in oracle 10g

SET LINESIZE 200

COLUMN latch_hit_ratio FORMAT 990.00

SELECT l.name,
       l.gets,
       l.misses,
       ((1 - (l.misses / l.gets)) * 100) AS latch_hit_ratio
FROM   v$latch l
WHERE  l.gets   != 0
UNION
SELECT l.name,
       l.gets,
       l.misses,
       100 AS latch_hit_ratio
FROM   v$latch l
WHERE  l.gets   = 0
ORDER BY 4 DESC;