-20.12% is the change from 810 to 647
Calculation steps:
[( 647 - 810 ) ÷ 810] x 100 = -20.12%
Formula
Percentage change = [(647 - 810) / 810] x 100
Subtract the new number by the original number
647 - 810 = -163
-163 ÷ 810 = -0.20123456790123456
-0.20123456790123456 x 100 = -20.12%