-18.51% is the change from 821 to 669
Calculation steps:
[( 669 - 821 ) ÷ 821] x 100 = -18.51%
Formula
Percentage change = [(669 - 821) / 821] x 100
Subtract the new number by the original number
669 - 821 = -152
-152 ÷ 821 = -0.1851400730816078
-0.1851400730816078 x 100 = -18.51%