-37.14% is the change from 840 to 528
Calculation steps:
[( 528 - 840 ) ÷ 840] x 100 = -37.14%
Formula
Percentage change = [(528 - 840) / 840] x 100
Subtract the new number by the original number
528 - 840 = -312
-312 ÷ 840 = -0.37142857142857144
-0.37142857142857144 x 100 = -37.14%