11.7% is the change from 171 to 191
Calculation steps:
[( 191 - 171 ) ÷ 171] x 100 = 11.7%
Formula
Percentage change = [(191 - 171) / 171] x 100
Subtract the new number by the original number
191 - 171 = 20
20 ÷ 171 = 0.11695906432748537
0.11695906432748537 x 100 = 11.7%