-21.57% is the change from 830 to 651
Calculation steps:
[( 651 - 830 ) ÷ 830] x 100 = -21.57%
Formula
Percentage change = [(651 - 830) / 830] x 100
Subtract the new number by the original number
651 - 830 = -179
-179 ÷ 830 = -0.21566265060240963
-0.21566265060240963 x 100 = -21.57%