-5.47% is the change from 640 to 605
Calculation steps:
[( 605 - 640 ) ÷ 640] x 100 = -5.47%
Formula
Percentage change = [(605 - 640) / 640] x 100
Subtract the new number by the original number
605 - 640 = -35
-35 ÷ 640 = -0.0546875
-0.0546875 x 100 = -5.47%