-23.37% is the change from 830 to 636
Calculation steps:
[( 636 - 830 ) ÷ 830] x 100 = -23.37%
Formula
Percentage change = [(636 - 830) / 830] x 100
Subtract the new number by the original number
636 - 830 = -194
-194 ÷ 830 = -0.23373493975903614
-0.23373493975903614 x 100 = -23.37%