-6.09% is the change from 821 to 771
Calculation steps:
[( 771 - 821 ) ÷ 821] x 100 = -6.09%
Formula
Percentage change = [(771 - 821) / 821] x 100
Subtract the new number by the original number
771 - 821 = -50
-50 ÷ 821 = -0.06090133982947625
-0.06090133982947625 x 100 = -6.09%