-18.53% is the change from 491 to 400
Calculation steps:
[( 400 - 491 ) ÷ 491] x 100 = -18.53%
Formula
Percentage change = [(400 - 491) / 491] x 100
Subtract the new number by the original number
400 - 491 = -91
-91 ÷ 491 = -0.18533604887983707
-0.18533604887983707 x 100 = -18.53%