-21.08% is the change from 830 to 655
Calculation steps:
[( 655 - 830 ) ÷ 830] x 100 = -21.08%
Formula
Percentage change = [(655 - 830) / 830] x 100
Subtract the new number by the original number
655 - 830 = -175
-175 ÷ 830 = -0.21084337349397592
-0.21084337349397592 x 100 = -21.08%