-34.74% is the change from 521 to 340
Calculation steps:
[( 340 - 521 ) ÷ 521] x 100 = -34.74%
Formula
Percentage change = [(340 - 521) / 521] x 100
Subtract the new number by the original number
340 - 521 = -181
-181 ÷ 521 = -0.3474088291746641
-0.3474088291746641 x 100 = -34.74%