Pivot Table % Change Calculation

[dbmetcalf]

I created a pivot table (below) to compare Year over Year counts of items. I used the following expression to find the difference between counts, but can't figure out how to get the percent difference:

count(distinct XX) - after(count(distinct XX))

Here are the results of the above expression below. Any suggestions?

[dbmetcalf · Accepted solution]

Figured it out. I needed to add parenthesis around first expression.
((count(distinct XX) - after(count(distinct XX)))) / after(count(distinct XX))