-99.8% is the change from 501 to 1
Calculation steps:
[( 1 - 501 ) ÷ 501] x 100 = -99.8%
Formula
Percentage change = [(1 - 501) / 501] x 100
Subtract the new number by the original number
1 - 501 = -500
-500 ÷ 501 = -0.998003992015968
-0.998003992015968 x 100 = -99.8%