-0.1% is the change from 998 to 997
Calculation steps:
[( 997 - 998 ) ÷ 998] x 100 = -0.1%
Formula
Percentage change = [(997 - 998) / 998] x 100
Subtract the new number by the original number
997 - 998 = -1
-1 ÷ 998 = -0.001002004008016032
-0.001002004008016032 x 100 = -0.1%