-8.15% is the change from 491 to 451
Calculation steps:
[( 451 - 491 ) ÷ 491] x 100 = -8.15%
Formula
Percentage change = [(451 - 491) / 491] x 100
Subtract the new number by the original number
451 - 491 = -40
-40 ÷ 491 = -0.0814663951120163
-0.0814663951120163 x 100 = -8.15%