-20.71% is the change from 816 to 647
Calculation steps:
[( 647 - 816 ) ÷ 816] x 100 = -20.71%
Formula
Percentage change = [(647 - 816) / 816] x 100
Subtract the new number by the original number
647 - 816 = -169
-169 ÷ 816 = -0.20710784313725492
-0.20710784313725492 x 100 = -20.71%