-66.99% is the change from 521 to 172
Calculation steps:
[( 172 - 521 ) ÷ 521] x 100 = -66.99%
Formula
Percentage change = [(172 - 521) / 521] x 100
Subtract the new number by the original number
172 - 521 = -349
-349 ÷ 521 = -0.6698656429942419
-0.6698656429942419 x 100 = -66.99%