29.41% is the change from 170 to 220
Calculation steps:
[( 220 - 170 ) ÷ 170] x 100 = 29.41%
Formula
Percentage change = [(220 - 170) / 170] x 100
Subtract the new number by the original number
220 - 170 = 50
50 ÷ 170 = 0.29411764705882354
0.29411764705882354 x 100 = 29.41%