12.35% is the change from 170 to 191
Calculation steps:
[( 191 - 170 ) ÷ 170] x 100 = 12.35%
Formula
Percentage change = [(191 - 170) / 170] x 100
Subtract the new number by the original number
191 - 170 = 21
21 ÷ 170 = 0.12352941176470589
0.12352941176470589 x 100 = 12.35%