-9.89% is the change from 870 to 784
Calculation steps:
[( 784 - 870 ) ÷ 870] x 100 = -9.89%
Formula
Percentage change = [(784 - 870) / 870] x 100
Subtract the new number by the original number
784 - 870 = -86
-86 ÷ 870 = -0.09885057471264368
-0.09885057471264368 x 100 = -9.89%