-0.93% is the change from 642 to 636
Calculation steps:
[( 636 - 642 ) ÷ 642] x 100 = -0.93%
Formula
Percentage change = [(636 - 642) / 642] x 100
Subtract the new number by the original number
636 - 642 = -6
-6 ÷ 642 = -0.009345794392523364
-0.009345794392523364 x 100 = -0.93%