-34.97% is the change from 815 to 530
Calculation steps:
[( 530 - 815 ) ÷ 815] x 100 = -34.97%
Formula
Percentage change = [(530 - 815) / 815] x 100
Subtract the new number by the original number
530 - 815 = -285
-285 ÷ 815 = -0.3496932515337423
-0.3496932515337423 x 100 = -34.97%