50.31% is the change from 640 to 962
Calculation steps:
[( 962 - 640 ) ÷ 640] x 100 = 50.31%
Formula
Percentage change = [(962 - 640) / 640] x 100
Subtract the new number by the original number
962 - 640 = 322
322 ÷ 640 = 0.503125
0.503125 x 100 = 50.31%