-0.78% is the change from 641 to 636
Calculation steps:
[( 636 - 641 ) ÷ 641] x 100 = -0.78%
Formula
Percentage change = [(636 - 641) / 641] x 100
Subtract the new number by the original number
636 - 641 = -5
-5 ÷ 641 = -0.0078003120124804995
-0.0078003120124804995 x 100 = -0.78%