51.88% is the change from 640 to 972
Calculation steps:
[( 972 - 640 ) ÷ 640] x 100 = 51.88%
Formula
Percentage change = [(972 - 640) / 640] x 100
Subtract the new number by the original number
972 - 640 = 332
332 ÷ 640 = 0.51875
0.51875 x 100 = 51.88%