-19.98% is the change from 821 to 657
Calculation steps:
[( 657 - 821 ) ÷ 821] x 100 = -19.98%
Formula
Percentage change = [(657 - 821) / 821] x 100
Subtract the new number by the original number
657 - 821 = -164
-164 ÷ 821 = -0.1997563946406821
-0.1997563946406821 x 100 = -19.98%