-26.51% is the change from 830 to 610
Calculation steps:
[( 610 - 830 ) ÷ 830] x 100 = -26.51%
Formula
Percentage change = [(610 - 830) / 830] x 100
Subtract the new number by the original number
610 - 830 = -220
-220 ÷ 830 = -0.26506024096385544
-0.26506024096385544 x 100 = -26.51%