61.54% is the change from 13 to 21
Calculation steps:
[( 21 - 13 ) ÷ 13] x 100 = 61.54%
Formula
Percentage change = [(21 - 13) / 13] x 100
Subtract the new number by the original number
21 - 13 = 8
8 ÷ 13 = 0.6153846153846154
0.6153846153846154 x 100 = 61.54%