-99.8% is the change from 503 to 1
Calculation steps:
[( 1 - 503 ) ÷ 503] x 100 = -99.8%
Formula
Percentage change = [(1 - 503) / 503] x 100
Subtract the new number by the original number
1 - 503 = -502
-502 ÷ 503 = -0.9980119284294234
-0.9980119284294234 x 100 = -99.8%