-86.21% is the change from 290 to 40
Calculation steps:
[( 40 - 290 ) ÷ 290] x 100 = -86.21%
Formula
Percentage change = [(40 - 290) / 290] x 100
Subtract the new number by the original number
40 - 290 = -250
-250 ÷ 290 = -0.8620689655172413
-0.8620689655172413 x 100 = -86.21%