-90.63% is the change from 971 to 91
Calculation steps:
[( 91 - 971 ) ÷ 971] x 100 = -90.63%
Formula
Percentage change = [(91 - 971) / 971] x 100
Subtract the new number by the original number
91 - 971 = -880
-880 ÷ 971 = -0.9062821833161689
-0.9062821833161689 x 100 = -90.63%