-84.58% is the change from 830 to 128
Calculation steps:
[( 128 - 830 ) ÷ 830] x 100 = -84.58%
Formula
Percentage change = [(128 - 830) / 830] x 100
Subtract the new number by the original number
128 - 830 = -702
-702 ÷ 830 = -0.8457831325301205
-0.8457831325301205 x 100 = -84.58%