-1.15% is the change from 521 to 515
Calculation steps:
[( 515 - 521 ) ÷ 521] x 100 = -1.15%
Formula
Percentage change = [(515 - 521) / 521] x 100
Subtract the new number by the original number
515 - 521 = -6
-6 ÷ 521 = -0.011516314779270634
-0.011516314779270634 x 100 = -1.15%