-1.55% is the change from 646 to 636
Calculation steps:
[( 636 - 646 ) ÷ 646] x 100 = -1.55%
Formula
Percentage change = [(636 - 646) / 646] x 100
Subtract the new number by the original number
636 - 646 = -10
-10 ÷ 646 = -0.015479876160990712
-0.015479876160990712 x 100 = -1.55%