-57.23% is the change from 830 to 355
Calculation steps:
[( 355 - 830 ) ÷ 830] x 100 = -57.23%
Formula
Percentage change = [(355 - 830) / 830] x 100
Subtract the new number by the original number
355 - 830 = -475
-475 ÷ 830 = -0.572289156626506
-0.572289156626506 x 100 = -57.23%