-8.24% is the change from 340 to 312
Calculation steps:
[( 312 - 340 ) ÷ 340] x 100 = -8.24%
Formula
Percentage change = [(312 - 340) / 340] x 100
Subtract the new number by the original number
312 - 340 = -28
-28 ÷ 340 = -0.08235294117647059
-0.08235294117647059 x 100 = -8.24%