-73.49% is the change from 830 to 220
Calculation steps:
[( 220 - 830 ) ÷ 830] x 100 = -73.49%
Formula
Percentage change = [(220 - 830) / 830] x 100
Subtract the new number by the original number
220 - 830 = -610
-610 ÷ 830 = -0.7349397590361446
-0.7349397590361446 x 100 = -73.49%