-51.41% is the change from 815 to 396
Calculation steps:
[( 396 - 815 ) ÷ 815] x 100 = -51.41%
Formula
Percentage change = [(396 - 815) / 815] x 100
Subtract the new number by the original number
396 - 815 = -419
-419 ÷ 815 = -0.5141104294478528
-0.5141104294478528 x 100 = -51.41%