9.09% is the change from 770 to 840
Calculation steps:
[( 840 - 770 ) ÷ 770] x 100 = 9.09%
Formula
Percentage change = [(840 - 770) / 770] x 100
Subtract the new number by the original number
840 - 770 = 70
70 ÷ 770 = 0.09090909090909091
0.09090909090909091 x 100 = 9.09%