-93.86% is the change from 830 to 51
Calculation steps:
[( 51 - 830 ) ÷ 830] x 100 = -93.86%
Formula
Percentage change = [(51 - 830) / 830] x 100
Subtract the new number by the original number
51 - 830 = -779
-779 ÷ 830 = -0.9385542168674699
-0.9385542168674699 x 100 = -93.86%