-72.51% is the change from 331 to 91
Calculation steps:
[( 91 - 331 ) ÷ 331] x 100 = -72.51%
Formula
Percentage change = [(91 - 331) / 331] x 100
Subtract the new number by the original number
91 - 331 = -240
-240 ÷ 331 = -0.7250755287009063
-0.7250755287009063 x 100 = -72.51%