-16.62% is the change from 397 to 331
Calculation steps:
[( 331 - 397 ) ÷ 397] x 100 = -16.62%
Formula
Percentage change = [(331 - 397) / 397] x 100
Subtract the new number by the original number
331 - 397 = -66
-66 ÷ 397 = -0.16624685138539042
-0.16624685138539042 x 100 = -16.62%