18.52% is the change from 540 to 640
Calculation steps:
[( 640 - 540 ) ÷ 540] x 100 = 18.52%
Formula
Percentage change = [(640 - 540) / 540] x 100
Subtract the new number by the original number
640 - 540 = 100
100 ÷ 540 = 0.18518518518518517
0.18518518518518517 x 100 = 18.52%