-50.8% is the change from 811 to 399
Calculation steps:
[( 399 - 811 ) ÷ 811] x 100 = -50.8%
Formula
Percentage change = [(399 - 811) / 811] x 100
Subtract the new number by the original number
399 - 811 = -412
-412 ÷ 811 = -0.5080147965474723
-0.5080147965474723 x 100 = -50.8%