20.59% is the change from 680 to 820
Calculation steps:
[( 820 - 680 ) ÷ 680] x 100 = 20.59%
Formula
Percentage change = [(820 - 680) / 680] x 100
Subtract the new number by the original number
820 - 680 = 140
140 ÷ 680 = 0.20588235294117646
0.20588235294117646 x 100 = 20.59%