-5.7% is the change from 351 to 331
Calculation steps:
[( 331 - 351 ) ÷ 351] x 100 = -5.7%
Formula
Percentage change = [(331 - 351) / 351] x 100
Subtract the new number by the original number
331 - 351 = -20
-20 ÷ 351 = -0.05698005698005698
-0.05698005698005698 x 100 = -5.7%