-90.71% is the change from 840 to 78
Calculation steps:
[( 78 - 840 ) ÷ 840] x 100 = -90.71%
Formula
Percentage change = [(78 - 840) / 840] x 100
Subtract the new number by the original number
78 - 840 = -762
-762 ÷ 840 = -0.9071428571428571
-0.9071428571428571 x 100 = -90.71%