-99.84% is the change from 643 to 1
Calculation steps:
[( 1 - 643 ) ÷ 643] x 100 = -99.84%
Formula
Percentage change = [(1 - 643) / 643] x 100
Subtract the new number by the original number
1 - 643 = -642
-642 ÷ 643 = -0.9984447900466563
-0.9984447900466563 x 100 = -99.84%