-87.91% is the change from 819 to 99
Calculation steps:
[( 99 - 819 ) ÷ 819] x 100 = -87.91%
Formula
Percentage change = [(99 - 819) / 819] x 100
Subtract the new number by the original number
99 - 819 = -720
-720 ÷ 819 = -0.8791208791208791
-0.8791208791208791 x 100 = -87.91%