-83.37% is the change from 830 to 138
Calculation steps:
[( 138 - 830 ) ÷ 830] x 100 = -83.37%
Formula
Percentage change = [(138 - 830) / 830] x 100
Subtract the new number by the original number
138 - 830 = -692
-692 ÷ 830 = -0.8337349397590361
-0.8337349397590361 x 100 = -83.37%