Calculating Percentage between two columns

[Mr Steve Cox]

I have created a Pivot Table to count tickets completed vs tickets completed with a specific code (NLF). It is broken down by location and week within the reporting period. The main point of the table is to calculate what percentage of total tickets were coded with an NLF code, again broken down by location and week. Here is a screenshot:

I tried to do a calculated field, but my two fields "Closed Tickets" and "Coded NLF" were not available for putting into the formula. I simply need a third column showing that in Fayetteville, for example, 1 is 25% of 4. I also considered doing a column outside of the Pivot Table in Column D to do the calculation. That resulted in the following formula:
=GETPIVOTDATA("Coded NLF",$A$1,"System","Fayetteville","Date Created",DATE(2023,1,1))/GETPIVOTDATA("Closed Tickets",$A$1,"System","Fayetteville","Date Created",DATE(2023,1,1))
That gave the correct result for the first row, but dragging down Col D to fill did not adjust the formula for the rest of the pivot table. I can adjust it manually, but it is a large report and the source data will change (date ranges and which locations are represented) creating errors from some of the pivot table references. And so the formula would have to be rebuilt for each instance of the report.

Any help that you could give, either on the calculated field or on simplifying the calculation outside the pivot table would be greatly appreciated. Unfortunately, I am not able to link to the actual report or pivot table. I hope that I have given enough information to allow you to assist.
Thank you in advance!