-0.2% is the change from 999 to 997
Calculation steps:
[( 997 - 999 ) ÷ 999] x 100 = -0.2%
Formula
Percentage change = [(997 - 999) / 999] x 100
Subtract the new number by the original number
997 - 999 = -2
-2 ÷ 999 = -0.002002002002002002
-0.002002002002002002 x 100 = -0.2%