1900% is the change from 1 to 20
Calculation steps:
[( 20 - 1 ) ÷ 1] x 100 = 1900%
Formula
Percentage change = [(20 - 1) / 1] x 100
Subtract the new number by the original number
20 - 1 = 19
19 ÷ 1 = 19
19 x 100 = 1900%
Example