-54.35% is the change from 999 to 456
Calculation steps:
[( 456 - 999 ) ÷ 999] x 100 = -54.35%
Formula
Percentage change = [(456 - 999) / 999] x 100
Subtract the new number by the original number
456 - 999 = -543
-543 ÷ 999 = -0.5435435435435435
-0.5435435435435435 x 100 = -54.35%