-40.66% is the change from 878 to 521
Calculation steps:
[( 521 - 878 ) ÷ 878] x 100 = -40.66%
Formula
Percentage change = [(521 - 878) / 878] x 100
Subtract the new number by the original number
521 - 878 = -357
-357 ÷ 878 = -0.40660592255125283
-0.40660592255125283 x 100 = -40.66%