-39.02% is the change from 815 to 497
Calculation steps:
[( 497 - 815 ) ÷ 815] x 100 = -39.02%
Formula
Percentage change = [(497 - 815) / 815] x 100
Subtract the new number by the original number
497 - 815 = -318
-318 ÷ 815 = -0.3901840490797546
-0.3901840490797546 x 100 = -39.02%