-38.69% is the change from 840 to 515
Calculation steps:
[( 515 - 840 ) ÷ 840] x 100 = -38.69%
Formula
Percentage change = [(515 - 840) / 840] x 100
Subtract the new number by the original number
515 - 840 = -325
-325 ÷ 840 = -0.3869047619047619
-0.3869047619047619 x 100 = -38.69%