-33.73% is the change from 830 to 550
Calculation steps:
[( 550 - 830 ) ÷ 830] x 100 = -33.73%
Formula
Percentage change = [(550 - 830) / 830] x 100
Subtract the new number by the original number
550 - 830 = -280
-280 ÷ 830 = -0.3373493975903614
-0.3373493975903614 x 100 = -33.73%