1800% is the change from 1 to 19
Calculation steps:
[( 19 - 1 ) ÷ 1] x 100 = 1800%
Formula
Percentage change = [(19 - 1) / 1] x 100
Subtract the new number by the original number
19 - 1 = 18
18 ÷ 1 = 18
18 x 100 = 1800%
Example