-19.6% is the change from 398 to 320
Calculation steps:
[( 320 - 398 ) ÷ 398] x 100 = -19.6%
Formula
Percentage change = [(320 - 398) / 398] x 100
Subtract the new number by the original number
320 - 398 = -78
-78 ÷ 398 = -0.19597989949748743
-0.19597989949748743 x 100 = -19.6%