-80.2% is the change from 399 to 79
Calculation steps:
[( 79 - 399 ) ÷ 399] x 100 = -80.2%
Formula
Percentage change = [(79 - 399) / 399] x 100
Subtract the new number by the original number
79 - 399 = -320
-320 ÷ 399 = -0.8020050125313283
-0.8020050125313283 x 100 = -80.2%