Pivot table (calculation and/or sorting) problem

I am converting a table to a pivot table, so that it automatically updates and auto sorts when I import the new data each month.

The table is included with this post. I have a pivot table built with the fields I need. I would like to calculate "column j" divided by "column i" inside the pivot table, but cannot figure out after an hour off searching, how to do this.

Since I couldn't figure that out, I went ahead and just made the calculation work the typical way, but now I can't sort the pivot table by my new caculated field "column k".

Please help me understand how to refine this table to work correctly.

The only way I could get this to work, was to add a new column to your source data, which contained the number 1 for each row.

I could then add the calculated field to get your percentages and then able to sort.