-62.58% is the change from 815 to 305
Calculation steps:
[( 305 - 815 ) ÷ 815] x 100 = -62.58%
Formula
Percentage change = [(305 - 815) / 815] x 100
Subtract the new number by the original number
305 - 815 = -510
-510 ÷ 815 = -0.6257668711656442
-0.6257668711656442 x 100 = -62.58%