-2% is the change from 999 to 979
Calculation steps:
[( 979 - 999 ) ÷ 999] x 100 = -2%
Formula
Percentage change = [(979 - 999) / 999] x 100
Subtract the new number by the original number
979 - 999 = -20
-20 ÷ 999 = -0.02002002002002002
-0.02002002002002002 x 100 = -2%