-87.15% is the change from 646 to 83
Calculation steps:
[( 83 - 646 ) ÷ 646] x 100 = -87.15%
Formula
Percentage change = [(83 - 646) / 646] x 100
Subtract the new number by the original number
83 - 646 = -563
-563 ÷ 646 = -0.871517027863777
-0.871517027863777 x 100 = -87.15%