-6.59% is the change from 820 to 766
Calculation steps:
[( 766 - 820 ) ÷ 820] x 100 = -6.59%
Formula
Percentage change = [(766 - 820) / 820] x 100
Subtract the new number by the original number
766 - 820 = -54
-54 ÷ 820 = -0.06585365853658537
-0.06585365853658537 x 100 = -6.59%