-98.2% is the change from 999 to 18
Calculation steps:
[( 18 - 999 ) ÷ 999] x 100 = -98.2%
Formula
Percentage change = [(18 - 999) / 999] x 100
Subtract the new number by the original number
18 - 999 = -981
-981 ÷ 999 = -0.9819819819819819
-0.9819819819819819 x 100 = -98.2%