-89.77% is the change from 391 to 40
Calculation steps:
[( 40 - 391 ) ÷ 391] x 100 = -89.77%
Formula
Percentage change = [(40 - 391) / 391] x 100
Subtract the new number by the original number
40 - 391 = -351
-351 ÷ 391 = -0.8976982097186701
-0.8976982097186701 x 100 = -89.77%