-91.15% is the change from 870 to 77
Calculation steps:
[( 77 - 870 ) ÷ 870] x 100 = -91.15%
Formula
Percentage change = [(77 - 870) / 870] x 100
Subtract the new number by the original number
77 - 870 = -793
-793 ÷ 870 = -0.9114942528735632
-0.9114942528735632 x 100 = -91.15%