-20.78% is the change from 770 to 610
Calculation steps:
[( 610 - 770 ) ÷ 770] x 100 = -20.78%
Formula
Percentage change = [(610 - 770) / 770] x 100
Subtract the new number by the original number
610 - 770 = -160
-160 ÷ 770 = -0.2077922077922078
-0.2077922077922078 x 100 = -20.78%