-40.31% is the change from 320 to 191
Calculation steps:
[( 191 - 320 ) ÷ 320] x 100 = -40.31%
Formula
Percentage change = [(191 - 320) / 320] x 100
Subtract the new number by the original number
191 - 320 = -129
-129 ÷ 320 = -0.403125
-0.403125 x 100 = -40.31%