Query Redo Log Switch Rate

SET LINES 100
SET PAGESIZE 9999
SET VERIFY    OFF
COL DAY FORMAT a15;
COL HOUR FORMAT a4;
COL TOTAL FORMAT 999;

SELECT TO_CHAR(FIRST_TIME,'YYYY-MM-DD') DAY,
TO_CHAR(FIRST_TIME,'HH24') HOUR,
COUNT(*) TOTAL
FROM V$LOG_HISTORY
GROUP BY TO_CHAR(FIRST_TIME,'YYYY-MM-DD'),TO_CHAR(FIRST_TIME,'HH24')
ORDER BY TO_CHAR(FIRST_TIME,'YYYY-MM-DD'),TO_CHAR(FIRST_TIME,'HH24')
ASC;