-9.3% is the change from 430 to 390
Calculation steps:
[( 390 - 430 ) ÷ 430] x 100 = -9.3%
Formula
Percentage change = [(390 - 430) / 430] x 100
Subtract the new number by the original number
390 - 430 = -40
-40 ÷ 430 = -0.09302325581395349
-0.09302325581395349 x 100 = -9.3%