-97.93% is the change from 870 to 18
Calculation steps:
[( 18 - 870 ) ÷ 870] x 100 = -97.93%
Formula
Percentage change = [(18 - 870) / 870] x 100
Subtract the new number by the original number
18 - 870 = -852
-852 ÷ 870 = -0.9793103448275862
-0.9793103448275862 x 100 = -97.93%