1538.1% is the change from 21 to 344
Calculation steps:
[( 344 - 21 ) ÷ 21] x 100 = 1538.1%
Formula
Percentage change = [(344 - 21) / 21] x 100
Subtract the new number by the original number
344 - 21 = 323
323 ÷ 21 = 15.380952380952381
15.380952380952381 x 100 = 1538.1%