90.63% is the change from 320 to 610
Calculation steps:
[( 610 - 320 ) ÷ 320] x 100 = 90.63%
Formula
Percentage change = [(610 - 320) / 320] x 100
Subtract the new number by the original number
610 - 320 = 290
290 ÷ 320 = 0.90625
0.90625 x 100 = 90.63%