-50.51% is the change from 99 to 49
Calculation steps:
[( 49 - 99 ) ÷ 99] x 100 = -50.51%
Formula
Percentage change = [(49 - 99) / 99] x 100
Subtract the new number by the original number
49 - 99 = -50
-50 ÷ 99 = -0.5050505050505051
-0.5050505050505051 x 100 = -50.51%