-61.57% is the change from 830 to 319
Calculation steps:
[( 319 - 830 ) ÷ 830] x 100 = -61.57%
Formula
Percentage change = [(319 - 830) / 830] x 100
Subtract the new number by the original number
319 - 830 = -511
-511 ÷ 830 = -0.6156626506024097
-0.6156626506024097 x 100 = -61.57%