-90.57% is the change from 870 to 82
Calculation steps:
[( 82 - 870 ) ÷ 870] x 100 = -90.57%
Formula
Percentage change = [(82 - 870) / 870] x 100
Subtract the new number by the original number
82 - 870 = -788
-788 ÷ 870 = -0.9057471264367816
-0.9057471264367816 x 100 = -90.57%