67.74% is the change from 310 to 520
Calculation steps:
[( 520 - 310 ) ÷ 310] x 100 = 67.74%
Formula
Percentage change = [(520 - 310) / 310] x 100
Subtract the new number by the original number
520 - 310 = 210
210 ÷ 310 = 0.6774193548387096
0.6774193548387096 x 100 = 67.74%