-75.43% is the change from 521 to 128
Calculation steps:
[( 128 - 521 ) ÷ 521] x 100 = -75.43%
Formula
Percentage change = [(128 - 521) / 521] x 100
Subtract the new number by the original number
128 - 521 = -393
-393 ÷ 521 = -0.7543186180422264
-0.7543186180422264 x 100 = -75.43%