-12.66% is the change from 640 to 559
Calculation steps:
[( 559 - 640 ) ÷ 640] x 100 = -12.66%
Formula
Percentage change = [(559 - 640) / 640] x 100
Subtract the new number by the original number
559 - 640 = -81
-81 ÷ 640 = -0.1265625
-0.1265625 x 100 = -12.66%