-19.95% is the change from 391 to 313
Calculation steps:
[( 313 - 391 ) ÷ 391] x 100 = -19.95%
Formula
Percentage change = [(313 - 391) / 391] x 100
Subtract the new number by the original number
313 - 391 = -78
-78 ÷ 391 = -0.19948849104859334
-0.19948849104859334 x 100 = -19.95%