-79.95% is the change from 399 to 80
Calculation steps:
[( 80 - 399 ) ÷ 399] x 100 = -79.95%
Formula
Percentage change = [(80 - 399) / 399] x 100
Subtract the new number by the original number
80 - 399 = -319
-319 ÷ 399 = -0.7994987468671679
-0.7994987468671679 x 100 = -79.95%