-91.85% is the change from 491 to 40
Calculation steps:
[( 40 - 491 ) ÷ 491] x 100 = -91.85%
Formula
Percentage change = [(40 - 491) / 491] x 100
Subtract the new number by the original number
40 - 491 = -451
-451 ÷ 491 = -0.9185336048879837
-0.9185336048879837 x 100 = -91.85%