-87.68% is the change from 641 to 79
Calculation steps:
[( 79 - 641 ) ÷ 641] x 100 = -87.68%
Formula
Percentage change = [(79 - 641) / 641] x 100
Subtract the new number by the original number
79 - 641 = -562
-562 ÷ 641 = -0.8767550702028081
-0.8767550702028081 x 100 = -87.68%