How to check how many switches occur per day in last 100 days?

set pagesize 200 Select    to_char(trunc(first_time), 'Month') Month,    to_char(trunc(first_time), 'Mon-DD-YYYY  :DY') Date_n_Day,    count(*) Total_logswitches from    v$log_history where    trunc(first_time) > last_day(sysdate-100) +1 group by    trunc(first_time) order by 2 desc;