-37.42% is the change from 831 to 520
Calculation steps:
[( 520 - 831 ) ÷ 831] x 100 = -37.42%
Formula
Percentage change = [(520 - 831) / 831] x 100
Subtract the new number by the original number
520 - 831 = -311
-311 ÷ 831 = -0.3742478941034898
-0.3742478941034898 x 100 = -37.42%