Trying to get percentage of results

Your formula does not do a division anywhere to determine a percentage, so I don't know how you were expecting your formula to yield a percentage. You are not using COUNTIF correctly; I'm not sure what you intend with 1, 2, and 3 as the second argument.

The only interpretation I have of your description is what is the percentage out of those 5 values. So the percentage for any given range can only be 0%, 20%, 40%, 60%, 80%, or 100%. If that is not correct then you need to explain what you mean by a "percentage of the results."

You are doing three things in your sheet design that are making your life harder:

1. You are doing analysis on a discontiguous range. It is difficult to use COUNTIFS (you need that along with COUNTIF) with a discontiguous range, although it's possible.
2. You are generating your result in a single cell. It would easier and probably look better to separate your results into three cells. This would also eliminate the need to use TEXT for formatting.
3. You are baking constants into your formula. It would be better to make a table that shows the minimum and maximum values of each range.

If you were to do those three things you would have a very simple formula. Instead you have this:

="0-15: "&TEXT(SUM(COUNTIF(INDIRECT({"C32","F32","I32","L32","O32"}),"<=15"))/SUM(COUNTA(INDIRECT({"C32","F32","I32","L32","O32"}))),"0%")&" 16-29 : "&TEXT(SUM(COUNTIFS(INDIRECT({"C32","F32","I32","L32","O32"}),">=16",INDIRECT({"C32","F32","I32","L32","O32"}),"<=29"))/SUM(COUNTA(INDIRECT({"C32","F32","I32","L32","O32"}))),"0%")&" 30+: "&TEXT(SUM(COUNTIF(INDIRECT({"C32","F32","I32","L32","O32"}),">=30"))/SUM(COUNTA(INDIRECT({"C32","F32","I32","L32","O32"}))),"0%")

You'll have to add a check for A25, which will make it even more complicated.