31.41% is the change from 640 to 841
Calculation steps:
[( 841 - 640 ) ÷ 640] x 100 = 31.41%
Formula
Percentage change = [(841 - 640) / 640] x 100
Subtract the new number by the original number
841 - 640 = 201
201 ÷ 640 = 0.3140625
0.3140625 x 100 = 31.41%