6.49% is the change from 770 to 820
Calculation steps:
[( 820 - 770 ) ÷ 770] x 100 = 6.49%
Formula
Percentage change = [(820 - 770) / 770] x 100
Subtract the new number by the original number
820 - 770 = 50
50 ÷ 770 = 0.06493506493506493
0.06493506493506493 x 100 = 6.49%