"NaN" on the Dashboard

I have a rather simple measure that compares the percentage rise (fall) in current year net proit against the prior year:

2016-2015 Net Profit % Increase (Decrease) = FORMAT((GLSACCOUNT[2016 Net Income]-GLSACCOUNT[2015 Net Income]) / GLSACCOUNT[2015 Net Income], "Percent")

This works fine in the online Report properly showing the percent increase/decrease, but when I pin it to the Dashboard it shows "NaN" which, to my understanding, means, "not a number."

Any thoughts on why I am seeing this behavior?

Thanks.