-19.44% is the change from 391 to 315
Calculation steps:
[( 315 - 391 ) ÷ 391] x 100 = -19.44%
Formula
Percentage change = [(315 - 391) / 391] x 100
Subtract the new number by the original number
315 - 391 = -76
-76 ÷ 391 = -0.19437340153452684
-0.19437340153452684 x 100 = -19.44%