-45% is the change from 180 to 99
Calculation steps:
[( 99 - 180 ) ÷ 180] x 100 = -45%
Formula
Percentage change = [(99 - 180) / 180] x 100
Subtract the new number by the original number
99 - 180 = -81
-81 ÷ 180 = -0.45
-0.45 x 100 = -45%
Example