2.7% is the change from 666 to 684
Calculation steps:
[( 684 - 666 ) ÷ 666] x 100 = 2.7%
Formula
Percentage change = [(684 - 666) / 666] x 100
Subtract the new number by the original number
684 - 666 = 18
18 ÷ 666 = 0.02702702702702703
0.02702702702702703 x 100 = 2.7%