-39.39% is the change from 815 to 494
Calculation steps:
[( 494 - 815 ) ÷ 815] x 100 = -39.39%
Formula
Percentage change = [(494 - 815) / 815] x 100
Subtract the new number by the original number
494 - 815 = -321
-321 ÷ 815 = -0.39386503067484663
-0.39386503067484663 x 100 = -39.39%