2030% is the change from 30 to 639
Calculation steps:
[( 639 - 30 ) ÷ 30] x 100 = 2030%
Formula
Percentage change = [(639 - 30) / 30] x 100
Subtract the new number by the original number
639 - 30 = 609
609 ÷ 30 = 20.3
20.3 x 100 = 2030%
Example