-96.1% is the change from 999 to 39
Calculation steps:
[( 39 - 999 ) ÷ 999] x 100 = -96.1%
Formula
Percentage change = [(39 - 999) / 999] x 100
Subtract the new number by the original number
39 - 999 = -960
-960 ÷ 999 = -0.960960960960961
-0.960960960960961 x 100 = -96.1%