column  file#           format 999          Heading "File"
column  ct              format 9999999999   heading "Waits"
column  time            format 999999   heading "Time"
column  avg             format 999.999  heading "Avg time"

select 
        indx+1          file#,
        count           ct,
        time,
        time/(decode(count,0,1,count))  avg
from x$kcbfwait
where
        indx < (select count(*) from v$datafile)
order by 2 desc
;