862.5% is the change from 80 to 770
Calculation steps:
[( 770 - 80 ) ÷ 80] x 100 = 862.5%
Formula
Percentage change = [(770 - 80) / 80] x 100
Subtract the new number by the original number
770 - 80 = 690
690 ÷ 80 = 8.625
8.625 x 100 = 862.5%
Example