-37.25% is the change from 816 to 512
Calculation steps:
[( 512 - 816 ) ÷ 816] x 100 = -37.25%
Formula
Percentage change = [(512 - 816) / 816] x 100
Subtract the new number by the original number
512 - 816 = -304
-304 ÷ 816 = -0.37254901960784315
-0.37254901960784315 x 100 = -37.25%