-10.9% is the change from 312 to 278
Calculation steps:
[( 278 - 312 ) ÷ 312] x 100 = -10.9%
Formula
Percentage change = [(278 - 312) / 312] x 100
Subtract the new number by the original number
278 - 312 = -34
-34 ÷ 312 = -0.10897435897435898
-0.10897435897435898 x 100 = -10.9%