-66.79% is the change from 521 to 173
Calculation steps:
[( 173 - 521 ) ÷ 521] x 100 = -66.79%
Formula
Percentage change = [(173 - 521) / 521] x 100
Subtract the new number by the original number
173 - 521 = -348
-348 ÷ 521 = -0.6679462571976967
-0.6679462571976967 x 100 = -66.79%