Your % Difference calculation has a table calculation applied to it, I know this because there's the triangle delta sign on the field. Please right click on the field and select clear table calculation.
My % Difference calculation is :
I've attached the workbook for you to review.
Percent Difference_v10.2.twbx 85.9 KB
I can see that your Diif % green pill in your view seems to be a Table Calculation. With your data like this (as in a separate columns for 2016 and 2017, there is no need to use the "%age Difference" quick table calculation, so just remove the table calculation.
Let me know if that doesn't do the trick, or doesn't make sense