-51.29% is the change from 815 to 397
Calculation steps:
[( 397 - 815 ) ÷ 815] x 100 = -51.29%
Formula
Percentage change = [(397 - 815) / 815] x 100
Subtract the new number by the original number
397 - 815 = -418
-418 ÷ 815 = -0.5128834355828221
-0.5128834355828221 x 100 = -51.29%