49.69% is the change from 640 to 958
Calculation steps:
[( 958 - 640 ) ÷ 640] x 100 = 49.69%
Formula
Percentage change = [(958 - 640) / 640] x 100
Subtract the new number by the original number
958 - 640 = 318
318 ÷ 640 = 0.496875
0.496875 x 100 = 49.69%