OK, here's my situation:

I have many columns of times. I need to find out what percentage of that
column is below 5 mins, which percentage is below 1 hour, which percentage is
above one hour, etc, etc.

I am using the following formula structu

=COUNTIF(A1:A100,"<0:05:00")/COUNT(A1:A100)
=COUNTIF(A1:A100,"1:00:00")/COUNT(A1:A100)
etc etc

Is is at all possible to create a custom function so that I don't have to
type all that stuff for every different range? Since some columns are
hundreds, other's are a small number, it's pretty random, so a custom
function would be ideal, with the range as the argument, however, i would
need to reference COUNTIF and COUNT, and i don't know how to do that or if it
is even at all possible.

Any help on this would be greatly appreciated!1 Thanks in advance ...