79.65% is the change from 172 to 309
Calculation steps:
[( 309 - 172 ) ÷ 172] x 100 = 79.65%
Formula
Percentage change = [(309 - 172) / 172] x 100
Subtract the new number by the original number
309 - 172 = 137
137 ÷ 172 = 0.7965116279069767
0.7965116279069767 x 100 = 79.65%