-75.24% is the change from 521 to 129
Calculation steps:
[( 129 - 521 ) ÷ 521] x 100 = -75.24%
Formula
Percentage change = [(129 - 521) / 521] x 100
Subtract the new number by the original number
129 - 521 = -392
-392 ÷ 521 = -0.7523992322456814
-0.7523992322456814 x 100 = -75.24%