81.56% is the change from 320 to 581
Calculation steps:
[( 581 - 320 ) ÷ 320] x 100 = 81.56%
Formula
Percentage change = [(581 - 320) / 320] x 100
Subtract the new number by the original number
581 - 320 = 261
261 ÷ 320 = 0.815625
0.815625 x 100 = 81.56%