-6.8% is the change from 338 to 315
Calculation steps:
[( 315 - 338 ) ÷ 338] x 100 = -6.8%
Formula
Percentage change = [(315 - 338) / 338] x 100
Subtract the new number by the original number
315 - 338 = -23
-23 ÷ 338 = -0.06804733727810651
-0.06804733727810651 x 100 = -6.8%