-39.64% is the change from 830 to 501
Calculation steps:
[( 501 - 830 ) ÷ 830] x 100 = -39.64%
Formula
Percentage change = [(501 - 830) / 830] x 100
Subtract the new number by the original number
501 - 830 = -329
-329 ÷ 830 = -0.3963855421686747
-0.3963855421686747 x 100 = -39.64%