698.75% is the change from 80 to 639
Calculation steps:
[( 639 - 80 ) ÷ 80] x 100 = 698.75%
Formula
Percentage change = [(639 - 80) / 80] x 100
Subtract the new number by the original number
639 - 80 = 559
559 ÷ 80 = 6.9875
6.9875 x 100 = 698.75%
Example