3.9% is the change from 770 to 800
Calculation steps:
[( 800 - 770 ) ÷ 770] x 100 = 3.9%
Formula
Percentage change = [(800 - 770) / 770] x 100
Subtract the new number by the original number
800 - 770 = 30
30 ÷ 770 = 0.03896103896103896
0.03896103896103896 x 100 = 3.9%