1540% is the change from 20 to 328
Calculation steps:
[( 328 - 20 ) ÷ 20] x 100 = 1540%
Formula
Percentage change = [(328 - 20) / 20] x 100
Subtract the new number by the original number
328 - 20 = 308
308 ÷ 20 = 15.4
15.4 x 100 = 1540%
Example