-1.9% is the change from 315 to 309
Calculation steps:
[( 309 - 315 ) ÷ 315] x 100 = -1.9%
Formula
Percentage change = [(309 - 315) / 315] x 100
Subtract the new number by the original number
309 - 315 = -6
-6 ÷ 315 = -0.01904761904761905
-0.01904761904761905 x 100 = -1.9%