-50.29% is the change from 521 to 259
Calculation steps:
[( 259 - 521 ) ÷ 521] x 100 = -50.29%
Formula
Percentage change = [(259 - 521) / 521] x 100
Subtract the new number by the original number
259 - 521 = -262
-262 ÷ 521 = -0.5028790786948176
-0.5028790786948176 x 100 = -50.29%