-22.7% is the change from 815 to 630
Calculation steps:
[( 630 - 815 ) ÷ 815] x 100 = -22.7%
Formula
Percentage change = [(630 - 815) / 815] x 100
Subtract the new number by the original number
630 - 815 = -185
-185 ÷ 815 = -0.22699386503067484
-0.22699386503067484 x 100 = -22.7%