-17.85% is the change from 521 to 428
Calculation steps:
[( 428 - 521 ) ÷ 521] x 100 = -17.85%
Formula
Percentage change = [(428 - 521) / 521] x 100
Subtract the new number by the original number
428 - 521 = -93
-93 ÷ 521 = -0.1785028790786948
-0.1785028790786948 x 100 = -17.85%