-49.49% is the change from 99 to 50
Calculation steps:
[( 50 - 99 ) ÷ 99] x 100 = -49.49%
Formula
Percentage change = [(50 - 99) / 99] x 100
Subtract the new number by the original number
50 - 99 = -49
-49 ÷ 99 = -0.494949494949495
-0.494949494949495 x 100 = -49.49%