-51.91% is the change from 813 to 391
Calculation steps:
[( 391 - 813 ) ÷ 813] x 100 = -51.91%
Formula
Percentage change = [(391 - 813) / 813] x 100
Subtract the new number by the original number
391 - 813 = -422
-422 ÷ 813 = -0.5190651906519065
-0.5190651906519065 x 100 = -51.91%