9.47% is the change from 285 to 312
Calculation steps:
[( 312 - 285 ) ÷ 285] x 100 = 9.47%
Formula
Percentage change = [(312 - 285) / 285] x 100
Subtract the new number by the original number
312 - 285 = 27
27 ÷ 285 = 0.09473684210526316
0.09473684210526316 x 100 = 9.47%