-20.12% is the change from 815 to 651
Calculation steps:
[( 651 - 815 ) ÷ 815] x 100 = -20.12%
Formula
Percentage change = [(651 - 815) / 815] x 100
Subtract the new number by the original number
651 - 815 = -164
-164 ÷ 815 = -0.20122699386503068
-0.20122699386503068 x 100 = -20.12%