-83.44% is the change from 815 to 135
Calculation steps:
[( 135 - 815 ) ÷ 815] x 100 = -83.44%
Formula
Percentage change = [(135 - 815) / 815] x 100
Subtract the new number by the original number
135 - 815 = -680
-680 ÷ 815 = -0.8343558282208589
-0.8343558282208589 x 100 = -83.44%