-26.35% is the change from 835 to 615
Calculation steps:
[( 615 - 835 ) ÷ 835] x 100 = -26.35%
Formula
Percentage change = [(615 - 835) / 835] x 100
Subtract the new number by the original number
615 - 835 = -220
-220 ÷ 835 = -0.2634730538922156
-0.2634730538922156 x 100 = -26.35%